Crosslinked polymers including sulfonic acid groups or salts or esters thereof as viscosifiers and fluid loss additives for subterranean treatment

ABSTRACT

Various embodiments disclosed relate to crosslinked polymers including sulfonic acid groups or salts or esters thereof as viscosifiers and fluid loss additives for subterranean treatment. In various embodiments, the present invention provides a method of treating a subterranean formation. The method includes placing in a subterranean formation a composition including a crosslinked viscosifier polymer including an ethylene repeating unit including an —S(O) 2 OR 1  group wherein at each occurrence R 1  is independently chosen from —H, substituted or unsubstituted (C 1 -C 20 )hydrocarbyl, and a counterion.

BACKGROUND

Various petroleum extraction subterranean formation treatment proceduresrequire use of compositions having high viscosities, such as duringdrilling or stimulation treatments. Various viscosifiers are used withclay in order to achieve a desired viscosity or degree of fluid losscontrol. Further, various viscosifiers are used with non-water-solubleweighting agents such as barite to provide a desired density. However,the use of clay and non-water-soluble weighting agents can cause severeformation damage due to plugging of the pores of the reservoir formationand due to difficulty of clean-up (e.g., clays are not water soluble).

Drill-in fluids, or reservoir drilling fluids, are a special type ofdrilling fluids used when drilling in the reservoir section of asubterranean formation. These fluids generally include base fluids (suchas brine), acid-soluble bridging agents, water-soluble polymers, pHstabilizers, and oxygen scavengers. Clays and non-water solubleweighting agents are generally avoided in drill-in fluids to preventpore plugging and to avoid difficult clean up. Instead, heavy brines aregenerally used to provide the density, and water-soluble orwater-swellable polymers are used as the rheology modifiers and fluidloss control agents. These polymers are generally biopolymers with atemperature limit below 300° F. At reservoir temperatures higher than300° F., synthetic water-soluble polymers can be used. However, manyviscosifiers cannot provide adequate viscosity at high temperatures,especially over time. In addition, many viscosifiers are not asefficient when used in brines. Thermal breakdown of polymers and highsalt content of the heavy brine used continue to pose a very challenginghurdle for high temperature applications.

Synthetic polymers for temperature control and fluid loss control athigh temperatures are generally linear or lightly crosslinked (e.g.,less than 1 mol % crosslinker) and need to be used with clay to achievedesired viscosity and fluid loss control. Without clay, unfortunately,these polymers cannot provide desired viscosity and fluid loss controlneeded for various subterranean treatments.

BRIEF DESCRIPTION OF THE FIGURES

The drawings illustrate generally, by way of example, but not by way oflimitation, various embodiments discussed in the present document.

FIG. 1 illustrates a drilling assembly, in accordance with variousembodiments.

FIG. 2 illustrates a system or apparatus for delivering a composition toa subterranean formation, in accordance with various embodiments.

DETAILED DESCRIPTION OF THE INVENTION

Reference will now be made in detail to certain embodiments of thedisclosed subject matter, examples of which are illustrated in part inthe accompanying drawings. While the disclosed subject matter will bedescribed in conjunction with the enumerated claims, it will beunderstood that the exemplified subject matter is not intended to limitthe claims to the disclosed subject matter.

Values expressed in a range format should be interpreted in a flexiblemanner to include not only the numerical values explicitly recited asthe limits of the range, but also to include all the individualnumerical values or sub-ranges encompassed within that range as if eachnumerical value and sub-range is explicitly recited. For example, arange of “about 0.1% to about 5%” or “about 0.1% to 5%” should beinterpreted to include not just about 0.1% to about 5%, but also theindividual values (e.g., 1%, 2%, 3%, and 4%) and the sub-ranges (e.g.,0.1% to 0.5%, 1.1% to 2.2%, 3.3% to 4.4%) within the indicated range.The statement “about X to Y” has the same meaning as “about X to aboutY,” unless indicated otherwise. Likewise, the statement “about X, Y, orabout Z” has the same meaning as “about X, about Y, or about Z,” unlessindicated otherwise.

In this document, the terms “a,” “an,” or “the” are used to include oneor more than one unless the context clearly dictates otherwise. The term“or” is used to refer to a nonexclusive “or” unless otherwise indicated.The statement “at least one of A and B” has the same meaning as “A, B,or A and B.” In addition, it is to be understood that the phraseology orterminology employed herein, and not otherwise defined, is for thepurpose of description only and not of limitation. Any use of sectionheadings is intended to aid reading of the document and is not to beinterpreted as limiting; information that is relevant to a sectionheading may occur within or outside of that particular section. A commacan be used as a delimiter or digit group separator to the left or rightof a decimal mark; for example, “0.000,1” is equivalent to “0.0001.”

In the methods of manufacturing described herein, the acts can becarried out in any order without departing from the principles of theinvention, except when a temporal or operational sequence is explicitlyrecited. Furthermore, specified acts can be carried out concurrentlyunless explicit claim language recites that they be carried outseparately. For example, a claimed act of doing X and a claimed act ofdoing Y can be conducted simultaneously within a single operation, andthe resulting process will fall within the literal scope of the claimedprocess.

The term “about” as used herein can allow for a degree of variability ina value or range, for example, within 10%, within 5%, within 1%, orwithin 0% of a stated value or of a stated limit of a range.

The term “substantially” as used herein refers to a majority of, ormostly, as in at least about 50%, 60%, 70%, 80%, 90%, 95%, 96%, 97%,98%, 99%, 99.5%, 99.9%, 99.99%, or at least about 99.999% or more.

The term “organic group” as used herein refers to but is not limited toany carbon-containing functional group. For example, anoxygen-containing group such as an alkoxy group, aryloxy group,aralkyloxy group, oxo(carbonyl) group, a carboxyl group including acarboxylic acid, carboxylate, and a carboxylate ester; asulfur-containing group such as an alkyl and aryl sulfide group; andother heteroatom-containing groups. Non-limiting examples of organicgroups include OR, OOR, OC(O)N(R)₂, CN, CF₃, OCF₃, R, C(O),methylenedioxy, ethylenedioxy, N(R)₂, SR, SOR, SO₂R, SO₂N(R)₂, SO₃R,C(O)R, C(O)C(O)R, C(O)CH₂C(O)R, C(S)R, C(O)OR, OC(O)R, C(O)N(R)₂,OC(O)N(R)₂, C(S)N(R)₂, (CH₂)₀₋₂N(R)C(O)R, (CH₂)₀₋₂N(R)N(R)₂,N(R)N(R)C(O)R, N(R)N(R)C(O)OR, N(R)N(R)CON(R)₂, N(R)SO₂R, N(R)SO₂N(R)₂,N(R)C(O)OR, N(R)C(O)R, N(R)C(S)R, N(R)C(O)N(R)₂, N(R)C(S)N(R)₂,N(COR)COR, N(OR)R, C(═NH)N(R)₂, C(O)N(OR)R, C(═NOR)R, and substituted orunsubstituted (C₁-C₁₀₀)hydrocarbyl, wherein R can be hydrogen (inexamples that include other carbon atoms) or a carbon-based moiety, andwherein the carbon-based moiety can itself be substituted orunsubstituted.

The term “substituted” as used herein refers to an organic group asdefined herein or molecule in which one or more hydrogen atoms containedtherein are replaced by one or more non-hydrogen atoms. The term“functional group” or “substituent” as used herein refers to a groupthat can be or is substituted onto a molecule or onto an organic group.Examples of substituents or functional groups include, but are notlimited to, a halogen (e.g., F, Cl, Br, and I); an oxygen atom in groupssuch as hydroxy groups, alkoxy groups, aryloxy groups, aralkyloxygroups, oxo(carbonyl) groups, carboxyl groups including carboxylicacids, carboxylates, and carboxylate esters; a sulfur atom in groupssuch as thiol groups, alkyl and aryl sulfide groups, sulfoxide groups,sulfone groups, sulfonyl groups, and sulfonamide groups; a nitrogen atomin groups such as amines, hydroxyamines, nitriles, nitro groups,N-oxides, hydrazides, azides, and enamines; and other heteroatoms invarious other groups. Non-limiting examples of substituents that can bebonded to a substituted carbon (or other) atom include F, Cl, Br, I, OR,OC(O)N(R)₂, CN, NO, NO₂, ONO₂, azido, CF₃, OCF₃, R, O (oxo), S (thiono),C(O), S(O), methylenedioxy, ethylenedioxy, N(R)₂, SR, SOR, SO₂R,SO₂N(R)₂, SO₃R, C(O)R, C(O)C(O)R, C(O)CH₂C(O)R, C(S)R, C(O)OR, OC(O)R,C(O)N(R)₂, OC(O)N(R)₂, C(S)N(R)₂, (CH₂)₀₋₂N(R)C(O)R, (CH₂)₀₋₂N(R)N(R)₂,N(R)N(R)C(O)R, N(R)N(R)C(O)OR, N(R)N(R)CON(R)₂, N(R)SO₂R, N(R)SO₂N(R)₂,N(R)C(O)OR, N(R)C(O)R, N(R)C(S)R, N(R)C(O)N(R)₂, N(R)C(S)N(R)₂,N(COR)COR, N(OR)R, C(═NH)N(R)₂, C(O)N(OR)R, and C(═NOR)R, wherein R canbe hydrogen or a carbon-based moiety; for example, R can be hydrogen,(C₁-C₁₀₀)hydrocarbyl, alkyl, acyl, cycloalkyl, aryl, aralkyl,heterocyclyl, heteroaryl, or heteroarylalkyl; or wherein two R groupsbonded to a nitrogen atom or to adjacent nitrogen atoms can togetherwith the nitrogen atom or atoms form a heterocyclyl.

The term “alkyl” as used herein refers to straight chain and branchedalkyl groups and cycloalkyl groups having from 1 to 40 carbon atoms, 1to about 20 carbon atoms, 1 to 12 carbons or, in some embodiments, from1 to 8 carbon atoms. Examples of straight chain alkyl groups includethose with from 1 to 8 carbon atoms such as methyl, ethyl, n-propyl,n-butyl, n-pentyl, n-hexyl, n-heptyl, and n-octyl groups. Examples ofbranched alkyl groups include, but are not limited to, isopropyl,iso-butyl, sec-butyl, t-butyl, neopentyl, isopentyl, and2,2-dimethylpropyl groups. As used herein, the term “alkyl” encompassesn-alkyl, isoalkyl, and anteisoalkyl groups as well as other branchedchain forms of alkyl. Representative substituted alkyl groups can besubstituted one or more times with any of the groups listed herein, forexample, amino, hydroxy, cyano, carboxy, nitro, thio, alkoxy, andhalogen groups.

The term “alkenyl” as used herein refers to straight and branched chainand cyclic alkyl groups as defined herein, except that at least onedouble bond exists between two carbon atoms. Thus, alkenyl groups havefrom 2 to 40 carbon atoms, or 2 to about 20 carbon atoms, or 2 to 12carbons or, in some embodiments, from 2 to 8 carbon atoms. Examplesinclude, but are not limited to vinyl, —CH═CH(CH₃), —CH═C(CH₃)₂,—C(CH₃)═CH₂, —C(CH₃)═CH(CH₃), —C(CH₂CH₃)═CH₂, cyclohexenyl,cyclopentenyl, cyclohexadienyl, butadienyl, pentadienyl, and hexadienylamong others.

The term “acyl” as used herein refers to a group containing a carbonylmoiety wherein the group is bonded via the carbonyl carbon atom. Thecarbonyl carbon atom is also bonded to another carbon atom, which can bepart of an alkyl, aryl, aralkyl cycloalkyl, cycloalkylalkyl,heterocyclyl, heterocyclylalkyl, heteroaryl, heteroarylalkyl group orthe like. In the special case wherein the carbonyl carbon atom is bondedto a hydrogen, the group is a “formyl” group, an acyl group as the termis defined herein. An acyl group can include 0 to about 12-20 or 12-40additional carbon atoms bonded to the carbonyl group. An acyl group caninclude double or triple bonds within the meaning herein. An acryloylgroup is an example of an acyl group. An acyl group can also includeheteroatoms within the meaning here. A nicotinoyl group(pyridyl-3-carbonyl) is an example of an acyl group within the meaningherein. Other examples include acetyl, benzoyl, phenylacetyl,pyridylacetyl, cinnamoyl, and acryloyl groups and the like. When thegroup containing the carbon atom that is bonded to the carbonyl carbonatom contains a halogen, the group is termed a “haloacyl” group. Anexample is a trifluoroacetyl group.

The term “aryl” as used herein refers to cyclic aromatic hydrocarbonsthat do not contain heteroatoms in the ring. Thus aryl groups include,but are not limited to, phenyl, azulenyl, heptalenyl, biphenyl,indacenyl, fluorenyl, phenanthrenyl, triphenylenyl, pyrenyl,naphthacenyl, chrysenyl, biphenylenyl, anthracenyl, and naphthyl groups.In some embodiments, aryl groups contain about 6 to about 14 carbons inthe ring portions of the groups. Aryl groups can be unsubstituted orsubstituted, as defined herein. Representative substituted aryl groupscan be mono-substituted or substituted more than once, such as, but notlimited to, 2-, 3-, 4-, 5-, or 6-substituted phenyl or 2-8 substitutednaphthyl groups, which can be substituted with carbon or non-carbongroups such as those listed herein.

The term “heterocyclyl” as used herein refers to aromatic andnon-aromatic ring compounds containing three or more ring members, ofwhich one or more is a heteroatom such as, but not limited to, N, O, andS. Thus, a heterocyclyl can be a cycloheteroalkyl, or a heteroaryl, orif polycyclic, any combination thereof. In some embodiments,heterocyclyl groups include 3 to about 20 ring members, whereas othersuch groups have 3 to about 15 ring members. A heterocyclyl groupdesignated as a C₂-heterocyclyl can be a 5-ring with two carbon atomsand three heteroatoms, a 6-ring with two carbon atoms and fourheteroatoms and so forth. Likewise a C₄-heterocyclyl can be a 5-ringwith one heteroatom, a 6-ring with two heteroatoms, and so forth. Thenumber of carbon atoms plus the number of heteroatoms equals the totalnumber of ring atoms. A heterocyclyl ring can also include one or moredouble bonds. A heteroaryl ring is an embodiment of a heterocyclylgroup. The phrase “heterocyclyl group” includes fused ring speciesincluding those that include fused aromatic and non-aromatic groups.

The terms “halo,” “halogen,” or “halide” group, as used herein, bythemselves or as part of another substituent, mean, unless otherwisestated, a fluorine, chlorine, bromine, or iodine atom.

The term “haloalkyl” group, as used herein, includes mono-halo alkylgroups, poly-halo alkyl groups wherein all halo atoms can be the same ordifferent, and per-halo alkyl groups, wherein all hydrogen atoms arereplaced by halogen atoms, such as fluoro. Examples of haloalkyl includetrifluoromethyl, 1,1-dichloroethyl, 1,2-dichloroethyl,1,3-dibromo-3,3-difluoropropyl, perfluorobutyl, and the like.

The term “hydrocarbon” as used herein refers to a functional group ormolecule that includes carbon and hydrogen atoms. The term can alsorefer to a functional group or molecule that normally includes bothcarbon and hydrogen atoms but wherein all the hydrogen atoms aresubstituted with other functional groups.

As used herein, the term “hydrocarbyl” refers to a functional groupderived from a straight chain, branched, or cyclic hydrocarbon, and canbe alkyl, alkenyl, alkynyl, aryl, cycloalkyl, acyl, or any combinationthereof.

The term “solvent” as used herein refers to a liquid that can dissolve asolid, liquid, or gas. Non-limiting examples of solvents are silicones,organic compounds, water, alcohols, ionic liquids, and supercriticalfluids.

The term “number-average molecular weight” as used herein refers to theordinary arithmetic mean of the molecular weight of individual moleculesin a sample. It is defined as the total weight of all molecules in asample divided by the total number of molecules in the sample.Experimentally, the number-average molecular weight (M_(n)) isdetermined by analyzing a sample divided into molecular weight fractionsof species i having n_(i) molecules of molecular weight M_(i) throughthe formula M_(n)=ΣM_(i)n_(i)/Σn_(i). The number-average molecularweight can be measured by a variety of well-known methods including gelpermeation chromatography, spectroscopic end group analysis, andosmometry. If unspecified, molecular weights of polymers given hereinare number-average molecular weights.

The term “weight-average molecular weight” as used herein refers toM_(w), which is equal to ΣM_(i) ²n_(i)/ΣM_(i)n_(i), where n_(i) is thenumber of molecules of molecular weight M_(i). In various examples, theweight-average molecular weight can be determined using lightscattering, small angle neutron scattering, X-ray scattering, andsedimentation velocity.

The term “room temperature” as used herein refers to a temperature ofabout 15° C. to 28° C.

The term “standard temperature and pressure” as used herein refers to20° C. and 101 kPa.

As used herein, “degree of polymerization” is the number of repeatingunits in a polymer.

As used herein, the term “polymer” refers to a molecule having at leastone repeating unit and can include copolymers.

The term “copolymer” as used herein refers to a polymer that includes atleast two different repeating units. A copolymer can include anysuitable number of repeating units.

The term “downhole” as used herein refers to under the surface of theearth, such as a location within or fluidly connected to a wellbore.

As used herein, the term “drilling fluid” refers to fluids, slurries, ormuds used in drilling operations downhole, such as during the formationof the wellbore.

As used herein, the term “stimulation fluid” refers to fluids orslurries used downhole during stimulation activities of the well thatcan increase the production of a well, including perforation activities.In some examples, a stimulation fluid can include a fracturing fluid oran acidizing fluid.

As used herein, the term “clean-up fluid” refers to fluids or slurriesused downhole during clean-up activities of the well, such as anytreatment to remove material obstructing the flow of desired materialfrom the subterranean formation. In one example, a clean-up fluid can bean acidification treatment to remove material formed by one or moreperforation treatments. In another example, a clean-up fluid can be usedto remove a filter cake.

As used herein, the term “fracturing fluid” refers to fluids or slurriesused downhole during fracturing operations.

As used herein, the term “spotting fluid” refers to fluids or slurriesused downhole during spotting operations, and can be any fluid designedfor localized treatment of a downhole region. In one example, a spottingfluid can include a lost circulation material for treatment of aspecific section of the wellbore, such as to seal off fractures in thewellbore and prevent sag. In another example, a spotting fluid caninclude a water control material. In some examples, a spotting fluid canbe designed to free a stuck piece of drilling or extraction equipment,can reduce torque and drag with drilling lubricants, preventdifferential sticking, promote wellbore stability, and can help tocontrol mud weight.

As used herein, the term “completion fluid” refers to fluids or slurriesused downhole during the completion phase of a well, including cementingcompositions.

As used herein, the term “remedial treatment fluid” refers to fluids orslurries used downhole for remedial treatment of a well. Remedialtreatments can include treatments designed to increase or maintain theproduction rate of a well, such as stimulation or clean-up treatments.

As used herein, the term “abandonment fluid” refers to fluids orslurries used downhole during or preceding the abandonment phase of awell.

As used herein, the term “acidizing fluid” refers to fluids or slurriesused downhole during acidizing treatments. In one example, an acidizingfluid is used in a clean-up operation to remove material obstructing theflow of desired material, such as material formed during a perforationoperation. In some examples, an acidizing fluid can be used for damageremoval.

As used herein, the term “cementing fluid” refers to fluids or slurriesused during cementing operations of a well. For example, a cementingfluid can include an aqueous mixture including at least one of cementand cement kiln dust. In another example, a cementing fluid can includea curable resinous material such as a polymer that is in an at leastpartially uncured state.

As used herein, the term “water control material” refers to a solid orliquid material that interacts with aqueous material downhole, such thathydrophobic material can more easily travel to the surface and such thathydrophilic material (including water) can less easily travel to thesurface. A water control material can be used to treat a well to causethe proportion of water produced to decrease and to cause the proportionof hydrocarbons produced to increase, such as by selectively bindingtogether material between water-producing subterranean formations andthe wellbore while still allowing hydrocarbon-producing formations tomaintain output.

As used herein, the term “packer fluid” refers to fluids or slurriesthat can be placed in the annular region of a well between tubing andouter casing above a packer. In various examples, the packer fluid canprovide hydrostatic pressure in order to lower differential pressureacross the sealing element, lower differential pressure on the wellboreand casing to prevent collapse, and protect metals and elastomers fromcorrosion.

As used herein, the term “fluid” refers to liquids and gels, unlessotherwise indicated.

As used herein, the term “subterranean material” or “subterraneanformation” refers to any material under the surface of the earth,including under the surface of the bottom of the ocean. For example, asubterranean formation or material can be any section of a wellbore andany section of a subterranean petroleum- or water-producing formation orregion in fluid contact with the wellbore. Placing a material in asubterranean formation can include contacting the material with anysection of a wellbore or with any subterranean region in fluid contacttherewith. Subterranean materials can include any materials placed intothe wellbore such as cement, drill shafts, liners, tubing, casing, orscreens; placing a material in a subterranean formation can includecontacting with such subterranean materials. In some examples, asubterranean formation or material can be any below-ground region thatcan produce liquid or gaseous petroleum materials, water, or any sectionbelow-ground in fluid contact therewith. For example, a subterraneanformation or material can be at least one of an area desired to befractured, a fracture or an area surrounding a fracture, and a flowpathway or an area surrounding a flow pathway, wherein a fracture or aflow pathway can be optionally fluidly connected to a subterraneanpetroleum- or water-producing region, directly or through one or morefractures or flow pathways.

As used herein, “treatment of a subterranean formation” can include anyactivity directed to extraction of water or petroleum materials from asubterranean petroleum- or water-producing formation or region, forexample, including drilling, stimulation, hydraulic fracturing,clean-up, acidizing, completion, cementing, remedial treatment,abandonment, and the like.

As used herein, a “flow pathway” downhole can include any suitablesubterranean flow pathway through which two subterranean locations arein fluid connection. The flow pathway can be sufficient for petroleum orwater to flow from one subterranean location to the wellbore orvice-versa. A flow pathway can include at least one of a hydraulicfracture, and a fluid connection across a screen, across gravel pack,across proppant, including across resin-bonded proppant or proppantdeposited in a fracture, and across sand. A flow pathway can include anatural subterranean passageway through which fluids can flow. In someembodiments, a flow pathway can be a water source and can include water.In some embodiments, a flow pathway can be a petroleum source and caninclude petroleum. In some embodiments, a flow pathway can be sufficientto divert from a wellbore, fracture, or flow pathway connected theretoat least one of water, a downhole fluid, or a produced hydrocarbon.

As used herein, a “carrier fluid” refers to any suitable fluid forsuspending, dissolving, mixing, or emulsifying with one or morematerials to form a composition. For example, the carrier fluid can beat least one of crude oil, dipropylene glycol methyl ether, dipropyleneglycol dimethyl ether, dipropylene glycol methyl ether, dipropyleneglycol dimethyl ether, dimethyl formamide, diethylene glycol methylether, ethylene glycol butyl ether, diethylene glycol butyl ether,butylglycidyl ether, propylene carbonate, D-limonene, a C₂-C₄₀ fattyacid C₁-C₁₀ alkyl ester (e.g., a fatty acid methyl ester),tetrahydrofurfuryl methacrylate, tetrahydrofurfuryl acrylate, 2-butoxyethanol, butyl acetate, butyl lactate, furfuryl acetate, dimethylsulfoxide, dimethyl formamide, a petroleum distillation product offraction (e.g., diesel, kerosene, napthas, and the like) mineral oil, ahydrocarbon oil, a hydrocarbon including an aromatic carbon-carbon bond(e.g., benzene, toluene), a hydrocarbon including an alpha olefin,xylenes, an ionic liquid, methyl ethyl ketone, an ester of oxalic,maleic or succinic acid, methanol, ethanol, propanol (iso- or normal-),butyl alcohol (iso-, tert-, or normal-), an aliphatic hydrocarbon (e.g.,cyclohexanone, hexane), water, brine, produced water, flowback water,brackish water, and sea water. The fluid can form about 0.001 wt % toabout 99.999 wt % of a composition, or a mixture including the same, orabout 0.001 wt % or less, 0.01 wt %, 0.1, 1, 2, 3, 4, 5, 6, 8, 10, 15,20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 96, 97,98, 99, 99.9, 99.99, or about 99.999 wt % or more.

In various embodiments, the present invention provides a method oftreating a subterranean formation. The method includes placing in asubterranean formation a composition. The composition includes acrosslinked viscosifier polymer that includes an ethylene repeatingunit. The ethylene repeating unit includes an —S(O)₂OR¹ group wherein ateach occurrence R¹ is independently chosen from —H, substituted orunsubstituted (C₁-C₂₀)hydrocarbyl, and a counterion.

In various embodiments, the present invention provides a method oftreating a subterranean formation. The method includes placing in asubterranean formation a composition including a crosslinked viscosifierpolymer including repeating units having the structure:

The repeating units are in a block, alternate, or random configuration,and each repeating unit is independently in the orientation shown or inthe opposite orientation. At each occurrence R^(A), R^(B), and R^(C) areindependently selected from the group consisting of —H and a substitutedor unsubstituted (C₁-C₅)hydrocarbyl. At each occurrence L¹ and L² areeach independently selected from the group consisting of a bond and asubstituted or unsubstituted (C₁-C₄₀)hydrocarbyl interrupted orterminated with 0, 1, 2, or 3 of at least one of —S—, —O—, andsubstituted or unsubstituted —NH—. At each occurrence the variable Z isindependently chosen from a —OR^(D) group, a —O—C(O)—R^(D) group, a—C(O)—NH₂ group, a —C(O)—NHR^(D) group, a —C(O)—NR^(D) ₂ group, a—C(O)—OH group or a salt thereof, a —C(O)—OR^(D) group, a—NR^(D)—C(O)—R^(D) group, and a —(C₁₋₂₀)heterocyclyl, wherein the—(C₁₋₂₀)heterocyclyl is a nitrogen-containing heterocycle substituentbound to the ethylene repeating unit via a nitrogen atom in theheterocyclic ring, and wherein R^(D) at each occurrence is independentlyselected from —H and substituted or unsubstituted (C₁-C₅₀)hydrocarbylinterrupted by 0, 1, 2, or 3 groups independently selected from —O—,—S—, and substituted or unsubstituted —NH—. At each occurrence L^(CL) isindependently chosen from a —((C₁-C₁₀)heterocyclylene)- and a-(substituted or unsubstituted (C₁-C₄₀)hydrocarbylene)-M, wherein the(C₁-C₄₀)hydrocarbylene is substituted or unsubstituted and isinterrupted by 0, 1, 2, or 3 groups independently selected from —O—,—S—, substituted or unsubstituted —NH—, and —((C₂-C₅)alkoxy)_(n)-,wherein at each occurrence M is independently an ethylene repeating unitof the same crosslinked viscosifier polymer molecule or an ethylenerepeating unit of another molecule of the crosslinked viscosifierpolymer. The crosslinked viscosifier polymer has about A^(mol) mol % ofthe repeating unit including the —S(O)₂OR¹, wherein A^(mol) is about 30mol % to about 99 mol %, the crosslinked viscosifier polymer has aboutB^(mol) mol % of the comonomer b, wherein B^(mol) is about 0 mol % toabout 70 mol %, wherein the crosslinked viscosifier polymer has aboutC^(mol) mol % of the comonomer c, wherein C^(mol) is about 0.01 mol % toabout 30 mol %.

In various embodiments, the present invention provides a method oftreating a subterranean formation. The method includes placing in asubterranean formation a composition including a crosslinked viscosifierpolymer including repeating units having the structure:

The repeating units are in a block, alternate, or random configuration,and each repeating unit is independently in the orientation shown or inthe opposite orientation. At each occurrence R^(A), R^(B), and R^(C) areindependently selected from the group consisting of —H and (C₁-C₅)alkyl.At each occurrence the variable Z is independently chosen from an —OHgroup, a —OR^(D) group, a —O—C(O)—R^(D) group, a —C(O)—NH₂ group, a—C(O)—OH group or a salt or (C₁-C₅) alkyl ester thereof, a —C(O)—OR^(D)group, and —N-pyrrolidinyl, wherein R^(D) at each occurrence isindependently (C₁-C₅)alkyl. At each occurrence L^(CL) is independentlychosen from —C(O)—NH—CH₂—NH—C(O)-M, —C(O)—NH—CH₂—CH₂—NH—C(O)-M,—C(O)—(O—CH₂—CH₂)_(n2)—O—C(O)-M, —C(O)—(O—CH₂—CH₂—CH₂)_(n2)—O—C(O)-M,—C(O)—O—C(CH₂—CH₃)(O—C(O)-M)₂, —CH₂—O—CH₂—C(—CH₂—O—R^(CL3))₃, —O-M,—CH₂—O—CH₂-M, —CH₂—O-M, —O—CH₂-M, N,N-boundtetrahydropyrimidin-2(1H)-one, N,3-bound pyrrolidone, 1,3-bound2-imidazolidone, and N,N-bound pyrrolidone-R^(CL1)-pyrrolidone whereinthe pyrrolidones are bound to R^(CL1) via the 3-positions, whereinR^(CL3) at each occurrence is —CH₂-M or H, wherein at each occurrence Mis independently an ethylene repeating unit of the same crosslinkedviscosifier polymer molecule or an ethylene repeating unit of anothermolecule of the crosslinked viscosifier polymer. The crosslinkedviscosifier polymer has about A^(mol) mol % of the repeating unitincluding the —S(O)₂OR¹, wherein A^(mol) is about 30 mol % to about 99mol %, the crosslinked viscosifier polymer has about B^(mol) mol % ofthe comonomer b, wherein B^(mol) is about 0 mol % to about 70 mol %,wherein the crosslinked viscosifier polymer has about C^(mol) mol % ofthe comonomer c, wherein C^(mol) is about 0.01 mol % to about 30 mol %,wherein A^(mol)+B^(mol)+C^(mol) is about 100 mol %.

In various embodiments, the present invention provides a systemincluding a composition including a crosslinked viscosifier polymerincluding an ethylene repeating unit including an —S(O)₂OR¹ groupwherein at each occurrence R¹ is independently chosen from —H,substituted or unsubstituted (C₁-C₂₀)hydrocarbyl, and a counterion. Thesystem also includes a subterranean formation including the compositiontherein.

In various embodiments, the present invention provides a composition fortreatment of a subterranean formation. The composition includes acrosslinked viscosifier polymer including an ethylene repeating unitincluding an —S(O)₂OR¹ group wherein at each occurrence R¹ isindependently chosen from —H, substituted or unsubstituted(C₁-C₂₀)hydrocarbyl, and a counterion.

In various embodiments, the present invention provides a composition fortreatment of a subterranean formation. The composition includes acrosslinked viscosifier polymer including repeating units having thestructure:

The repeating units are in a block, alternate, or random configuration,and each repeating unit is independently in the orientation shown or inthe opposite orientation. At each occurrence R^(A), R^(B), and R^(C) areindependently selected from the group consisting of —H and a substitutedor unsubstituted (C₁-C₅)hydrocarbyl. At each occurrence L¹ and L² areeach independently selected from the group consisting of a bond and asubstituted or unsubstituted (C₁-C₄₀)hydrocarbyl interrupted orterminated with 0, 1, 2, or 3 of at least one of —S—, —O—, andsubstituted or unsubstituted —NH—. At each occurrence the variable Z isindependently chosen from a —OR^(D) group, a —O—C(O)—R^(D) group, a—C(O)—NH₂ group, a —C(O)—NHR^(D) group, a —C(O)—NR^(D) ₂ group, a—C(O)—OH group or a salt thereof, a —C(O)—OR^(D) group, a—NR^(D)—C(O)—R^(D) group, and a —(C₁₋₂₀)heterocyclyl, wherein the—(C₁₋₂₀)heterocyclyl is a nitrogen-containing heterocycle substituentbound to the ethylene repeating unit via a nitrogen atom in theheterocyclic ring, and wherein R^(D) at each occurrence is independentlyselected from —H and substituted or unsubstituted (C₁-C₅₀)hydrocarbylinterrupted by 0, 1, 2, or 3 groups independently selected from —O—,—S—, and substituted or unsubstituted —NH—. At each occurrence L^(CL) isindependently chosen from a —((C₁-C₁₀)heterocyclylene)- and a-(substituted or unsubstituted (C₁-C₄₀)hydrocarbylene)-M, wherein the(C₁-C₄₀)hydrocarbylene is substituted or unsubstituted and isinterrupted by 0, 1, 2, or 3 groups independently selected from —O—,—S—, substituted or unsubstituted —NH—, and —((C₂-C₅)alkoxy)_(n)-,wherein at each occurrence M is independently an ethylene repeating unitof the same crosslinked viscosifier polymer molecule or an ethylenerepeating unit of another molecule of the crosslinked viscosifierpolymer. The crosslinked viscosifier polymer has about A^(mol) mol % ofthe repeating unit including the —S(O)₂OR¹, wherein A^(mol) is about 30mol % to about 99 mol %, the crosslinked viscosifier polymer has aboutB^(mol) mol % of the comonomer b, wherein B^(mol) is about 0 mol % toabout 70 mol %, wherein the crosslinked viscosifier polymer has aboutC^(mol) mol % of the comonomer c, wherein C^(mol) is about 0.01 mol % toabout 30 mol %.

In various embodiments, the present invention provides a composition fortreatment of a subterranean formation. The composition includes acrosslinked viscosifier polymer including repeating units having thestructure:

The repeating units are in a block, alternate, or random configuration,and each repeating unit is independently in the orientation shown or inthe opposite orientation. At each occurrence R^(A), R^(B), and R^(C) areindependently selected from the group consisting of —H and (C₁-C₅)alkyl.At each occurrence the variable Z is independently chosen from an —OHgroup, a —OR^(D) group, a —O—C(O)—R^(D) group, a —C(O)—NH₂ group, a—C(O)—OH group or a salt or (C₁-C₅) alkyl ester thereof, a —C(O)—OR^(D)group, and —N-pyrrolidinyl, wherein R^(D) at each occurrence isindependently (C₁-C₅)alkyl. At each occurrence L^(CL) is independentlychosen from —C(O)—NH—CH₂—NH—C(O)-M, —C(O)—NH—CH₂—CH₂—NH—C(O)-M,—C(O)—(O—CH₂—CH₂)_(n2)—O—C(O)-M, —C(O)—(O—CH₂—CH₂—CH₂)_(n2)—O—C(O)-M,—C(O)—O—C(CH₂—CH₃)(O—C(O)-M)₂, —CH₂—O—CH₂—C(—CH₂—O—R^(CL3))₃, —O-M,—CH₂—O—CH₂-M, —CH₂—O-M, —O—CH₂-M, N,N-boundtetrahydropyrimidin-2(1H)-one, N,3-bound pyrrolidone, 1,3-bound2-imidazolidone, and N,N-bound pyrrolidone-R^(CL1)-pyrrolidone whereinthe pyrrolidones are bound to R^(CL1) via the 3-positions, whereinR^(CL3) at each occurrence is —CH₂-M or H, wherein at each occurrence Mis independently an ethylene repeating unit of the same crosslinkedviscosifier polymer molecule or an ethylene repeating unit of anothermolecule of the crosslinked viscosifier polymer. The crosslinkedviscosifier polymer has about A^(mol) mol % of the repeating unitincluding the —S(O)₂OR¹, wherein A^(mol) is about 30 mol % to about 99mol %, the crosslinked viscosifier polymer has about B^(mol) mol % ofthe comonomer b, wherein B^(mol) is about 0 mol % to about 70 mol %,wherein the crosslinked viscosifier polymer has about C^(mol) mol % ofthe comonomer c, wherein C^(mol) is about 0.01 mol % to about 30 mol %,and wherein A^(mol)+B^(mol)+C^(mol) is about 100 mol %.

In various embodiments, the present invention provides a method ofpreparing a composition for treatment of a subterranean formation. Themethod includes forming a composition including a crosslinkedviscosifier polymer including an ethylene repeating unit including an—S(O)₂OR¹ group wherein at each occurrence R¹ is independently chosenfrom —H, substituted or unsubstituted (C₁-C₂₀)hydrocarbyl, and acounterion.

Various embodiments of the present invention provide certain advantagesover other compositions including viscosifiers and methods of using thesame, at least some of which are unexpected. For example, in someembodiments, the crosslinked viscosifier polymer can provide sufficientviscosity or fluid loss control without the use of clay or with the useof less clay, avoiding or reducing the clogging of reservoir pores withclay, and avoiding or reducing the difficulty of cleaning after the useof clay. In various embodiments, the composition can provide betterviscosity and fluid loss characteristics than other compositions, suchas having a lower viscosity but maintaining low fluid loss under hightemperature and high pressure conditions. In various embodiments, ascompared to other linear or lightly crosslinked (e.g., less than 1 mol %crosslinker) polymers which fail to provide adequate viscosification andfluid loss control, especially in the presence of brines, thecrosslinked viscosifier polymer can provide effective viscosity andfluid loss control, even without the use of clays and in the presence ofheavy brines, and can in some embodiments be crosslinked with greaterthan 1 mol % crosslinker.

Many conventional viscosifiers suffer a decrease in the viscosityprovided and increase of fluid loss when used under high temperatureconditions such as the conditions found in many subterranean formations.In some embodiments, under high temperature conditions, the compositioncan have a higher viscosity or can experience less or no decrease inviscosity as compared to the viscosity provided by other compositionsunder corresponding conditions. In various embodiments, the highertemperature stability of the crosslinked viscosifier polymer can allow adesired level of viscosification with the use of less viscosifier, orcan allow a higher viscosity to be achieved in the subterraneanformation, as compared to other conventional viscosifiers, therebyproviding a more versatile, more cost effective, or more efficientviscosification in the subterranean formation than other methods andcompositions. In various embodiments, the composition can be lessexpensive per unit mass as compared to other viscous compositions forsubterranean treatment, such as other high-temperature-stable viscouscompositions.

For example, polyacrylamides can be incompatible with calcium carbonatebridging agents after aging due to hydrolysis of the amides to formpolyacrylate, causing precipitation of the calcium carbonate and thepolymer. However, in various embodiments, the composition including thecrosslinked viscosifier polymer can be compatible with calciumcarbonate, even after aging at high temperatures, such that thecomposition retains more viscosity or fluid loss control as compared toother compositions. In another example, viscosifier polymers crosslinkedwith hydrolyzable crosslinkers such as methylenebisacrylamide can behydrolyzed at high temperatures and with aging, causing loss ofviscosity and fluid loss control. However, in various embodiments, thecomposition including the crosslinked viscosifier can includecrosslinkers other than or in addition to methylenebisacrylamide (e.g.,pentaerythritol allyl ether) that are stable at high temperature andwith aging, resulting in better viscosification and fluid loss controlat high temperature over time as compared to other viscosifier polymersincluding a methylenebisacrylamide crosslinker.

Many conventional viscous compositions for subterranean use suffer adecrease in the viscosity provided when prepared with liquids such aswater having certain ions present at particular concentrations. Forexample, many viscosifiers suffer a decrease in the viscosity providedand increase of fluid loss when used with liquids having certain amountsof salts dissolved therein such as sodium chloride or potassiumchloride. Some viscosifiers can even precipitate out of solution in thepresence of divalent salts such as calcium chloride, especially whenused under high temperature conditions. In some embodiments, thecomposition can include liquids having ions dissolved therein and cansuffer less or no negative effects from the ions, as compared to otherviscous compositions for subterranean use, such as less or no decreasein viscosity. By being able to retain the viscosity provided or sufferless reduction in viscosity in the presence of various ions or in thepresence of larger amounts of particular ions than other methods andcompositions, various embodiments can avoid the need for ion-free orion-depleted water, or can avoid a need to add greater amounts ofviscosifier to achieve a desired effect in a subterranean formation, andcan thereby be more versatile, more cost effective, or more efficientthan other methods and compositions for subterranean use.

In various embodiments, by providing a higher viscosity under hightemperature conditions or high salinity conditions, the composition canbe a more effective downhole or subterranean fluid, such as a moreeffective drilling fluid that has greater cutting carrying capacity, sagresistance, fluid loss control, or equivalent circulating density, or amore effective hydraulic fracturing fluid that can more effectivelycarry proppant or form more dominant fractures. In various embodiments,the higher viscosity under high temperature conditions can make thecomposition a more thermally efficient packer fluid. In variousembodiments, by providing a higher viscosity under high temperatureconditions or high salinity conditions, the composition can be a moreeffective sweeping agent (e.g., for removing cuttings from thewellbore), can provide improved equivalent circulating densitymanagement, and can provide improved fluid loss control (e.g., thehigher viscosity can reduce fluid flow in pore spaces). In variousembodiments, the composition can be more effective for enhanced oilrecovery than other viscosifiers, providing better high temperaturestability and salt tolerance, reducing or minimizing fingering andincreasing sweep efficiency, enabling more oil recovery at a lower cost.

Method of Treating a Subterranean Formation.

In various embodiments, the present invention provides a method oftreating a subterranean formation. The method can include placing in asubterranean formation a crosslinked viscosifier polymer that includesan ethylene repeating unit including an —S(O)₂OR¹ group wherein at eachoccurrence R¹ is independently chosen from —H, substituted orunsubstituted (C₁-C₂₀)hydrocarbyl, and a counterion. The crosslinkedviscosifier polymer can act as a viscosifier and a filtration controlagent (providing fluid loss control). The crosslinked viscosifierpolymer in aqueous solution can be a polymeric gel or a polymericmicrogel. In various embodiments, the crosslinked viscosifier polymercan provide effective viscosification but also provide suitable fluidloss control, such as in substantially clay-free conditions, such as athigh temperature and high pressure conditions, including at temperaturesof up to 400° F., or up to and including 300° F., 305, 310, 315, 320,325, 330, 335, 340, 345, 350, 355, 360, 365, 370, 375, 380, 385, 390,395, 400, 405, 410, 415, 420, 425, 430, 435, 440, 445, or 450° F. ormore, such as for 3 days or more, or for about 1 day, 1.5, 2, 2.5, 3,3.5, 4, 4.5, 5, 5.5, 6, 6.5, or 7 or more days.

The obtaining or providing of the composition can occur at any suitabletime and at any suitable location. The obtaining or providing of thecomposition can occur above the surface. The obtaining or providing ofthe composition can occur in the subterranean formation. In someembodiments, the method can include mixing the crosslinked viscosifierpolymer and other components of the composition together. In someembodiments, the crosslinked viscosifier polymer and any othercomponents of the composition are already combined when the methodbegins. The method also includes placing the composition in asubterranean formation. The placing of the composition in thesubterranean formation can include contacting the composition and anysuitable part of the subterranean formation, or contacting thecomposition and a subterranean material, such as any suitablesubterranean material. The subterranean formation can be any suitablesubterranean formation. In some embodiments, the method is a method ofdrilling the subterranean formation, and the composition is a drillingfluid. In some embodiments, the composition is a drill-in fluid, whereinthe method includes drilling into a petroleum reservoir in thesubterranean formation using the composition. In some embodiments, thecomposition can have high compatibility and stability with drill solids.In some embodiments, the method is a method of fracturing thesubterranean formation. For example, the composition can be used as orwith a drilling fluid, hydraulic fracturing fluid, diverting fluid, or alost circulation treatment fluid.

In some examples, the placing of the composition in the subterraneanformation (e.g., downhole) includes contacting the composition with orplacing the composition in at least one of a fracture, at least a partof an area surrounding a fracture, a flow pathway, an area surrounding aflow pathway, and an area desired to be fractured. The placing of thecomposition in the subterranean formation can be any suitable placingand can include any suitable contacting between the subterraneanformation and the composition. The placing of the composition in thesubterranean formation can include at least partially depositing thecomposition in a fracture, flow pathway, or area surrounding the same.

The method can include hydraulic fracturing, such as a method ofhydraulic fracturing to generate a fracture or flow pathway. The placingof the composition in the subterranean formation or the contacting ofthe subterranean formation and the hydraulic fracturing can occur at anytime with respect to one another; for example, the hydraulic fracturingcan occur at least one of before, during, and after the contacting orplacing. In some embodiments, the contacting or placing occurs duringthe hydraulic fracturing, such as during any suitable stage of thehydraulic fracturing, such as during at least one of a pre-pad stage(e.g., during injection of water with no proppant, and additionallyoptionally mid- to low-strength acid), a pad stage (e.g., duringinjection of fluid only with no proppant, with some viscosifier, such asto begin to break into an area and initiate fractures to producesufficient penetration and width to allow proppant-laden later stages toenter), or a slurry stage of the fracturing (e.g., viscous fluid withproppant). The method can include performing a stimulation treatment atleast one of before, during, and after placing the composition in thesubterranean formation in the fracture, flow pathway, or areasurrounding the same. The stimulation treatment can be, for example, atleast one of perforating, acidizing, injecting of cleaning fluids,propellant stimulation, and hydraulic fracturing. In some embodiments,the stimulation treatment at least partially generates a fracture orflow pathway where the composition is placed or contacted, or thecomposition is placed or contacted to an area surrounding the generatedfracture or flow pathway.

The method can include diverting or fluid loss control. The compositioncan be delivered to the subterranean formation to a flowpath causingfluid loss or undesired introduction of water. The composition can havesufficient viscosity or fluid loss control such that the flowpath is atleast partially sealed, at least partially stopping fluid loss orpreventing water from entering the wellbore and contaminating fluidssuch as production fluids.

In some embodiments, in addition to the crosslinked viscosifier polymer,the composition can include at least one of an aqueous liquid and awater-miscible liquid. The method can further include mixing the aqueousliquid or water-miscible liquid with the crosslinked polymerviscosifier. The mixing can occur at any suitable time and at anysuitable location, such as above surface or in the subterraneanformation. The aqueous liquid can be any suitable aqueous liquid, suchas at least one of water, brine, produced water, flowback water,brackish water, and sea water. In some embodiments, the aqueous liquidcan include at least one of a drilling fluid, a hydraulic fracturingfluid, a diverting fluid, and a lost circulation treatment fluid. Thewater-miscible liquid can be any suitable water-miscible liquid, such asmethanol, ethanol, ethylene glycol, propylene glycol, glycerol, and thelike.

The composition can include any suitable proportion of the aqueousliquid or the water-miscible liquid, such that the composition can beused as described herein. For example, about 0.000,1 wt % to 99.999,9 wt% of the composition can be the aqueous liquid, water-miscible liquid,or combination thereof, or about 0.01 wt % to about 99.99 wt %, about0.1 wt % to about 99.9 wt %, or about 20 wt % to about 90 wt %, or about0.000,1 wt % or less, or about 0.000,001 wt %, 0.000,1, 0.001, 0.01,0.1, 1, 2, 3, 4, 5, 10, 15, 20, 30, 40, 50, 60, 70, 80, 85, 90, 91, 92,93, 94, 95, 96, 97, 98, 99, 99.9, 99.99, 99.999 wt %, or about 99.999,9wt % or more of the composition can be the aqueous liquid,water-miscible liquid, or a combination thereof.

The aqueous liquid can be a salt water. The salt can be any suitablesalt, such as at least one of NaBr, CaCl₂, CaBr₂, ZnBr₂, KCl, NaCl, amagnesium salt, a bromide salt, a formate salt, an acetate salt, and anitrate salt. The crosslinked viscosifier polymer can effectivelyprovide increased viscosity in aqueous solutions having various totaldissolved solids levels, or having various ppm salt concentration. Thecrosslinked viscosifier polymer can provide effective increasedviscosity of a salt water having any suitable total dissolved solidslevel, such as about 1,000 mg/L to about 250,000 mg/L, or about 1,000mg/L or less, or about 5,000 mg/L, 10,000, 15,000, 20,000, 25,000,30,000, 40,000, 50,000, 75,000, 100,000, 125,000, 150,000, 175,000,200,000, 225,000, or about 250,000 mg/L or more. The crosslinkedviscosifier polymer can provide effective increased viscosity of a saltwater having any suitable salt concentration, such as about 1,000 ppm toabout 300,000 ppm, or about 1,000 ppm to about 150,000 ppm, or about1,000 ppm or less, or about 5,000 ppm, 10,000, 15,000, 20,000, 25,000,30,000, 40,000, 50,000, 75,000, 100,000, 125,000, 150,000, 175,000,200,000, 225,000, 250,000, 275,000, or about 300,000 ppm or more. Insome examples, the aqueous liquid can have a concentration of at leastone of NaBr, CaCl₂, CaBr₂, ZnBr₂, KCl, and NaCl of about 0.1% w/v toabout 20% w/v, or about 0.1% w/v or less, or about 0.5% w/v, 1, 2, 3, 4,5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23,24, 25, 26, 27, 28, 29, or about 30% w/v or more.

The composition can have any suitable shear stress at a particular shearrate. For example, at 49° C. at standard pressure at a shear rate of 3rpm to 6 rpm, the composition can have a shear stress of about 1 lb/100ft² to about 40 lb/100 ft², or 2 lb/100 ft² to about 18 lb/100 ft², orabout 1 lb/100 ft² or less, or about 2 lb/100 ft², 3, 4, 5, 6, 7, 8, 9,10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 22, 24, 26, 28, 30, 32, 34,36, 38, or about 40 lb/100 ft² or more. At 49° C. at standard pressureat a shear rate of 200 rpm to 600 rpm, the composition can have a shearstress of about 15 lb/100 ft² to about 150 lb/100 ft², or about 20lb/100 ft² to about 135 lb/100 ft², or about 40 lb/100 ft² to about 130lb/100 ft², or about 15 lb/100 ft² or less, or about 20 lb/100 ft², 25,30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 100, 105, 110,115, 120, 125, 130, 135, 140, or about 150 lb/100 ft² or more. Thecomposition can have any suitable plastic viscosity, wherein the plasticviscosity represents the viscosity when extrapolated to infinite shearrate, e.g., the slope of the shear stress/shear rate line above theyield point. At 49° C. at standard pressure the composition can have aplastic viscosity of about 10 cP to about 60 cP, about 15 cP to about 40cP, or about 10 cP or less, or about 12, 14, 16, 18, 20, 22, 24, 26, 28,30, 32, 34, 36, 38, 40, 42, 44, 46, 48, 50, 52, 54, 56, 58, or about 60cP or more. The composition can have any suitable yield point, whereinthe yield point is the yield stress extrapolated to a shear rate ofzero. At 49° C. at standard pressure the composition can have a yieldpoint of about 10 lb/100 ft² to about 80 lb/100 ft², about 15 lb/100 ft²to about 60 lb/100 ft², or about 10 lb/100 ft² or less, or about 12 14,16, 18, 20, 22, 24, 26, 28, 30, 32, 34, 36, 38, 40, 42, 44, 46, 48, 50,52, 54, 56, 58, 60, 62, 64, 66, 68, 70, 72, 74, 76, 78, or about 80lb/100 ft² or more. The composition can have any suitable fluid losscontrol properties, for example, at 177° C. using a 20 micron ceramicdisc at 500 psi differential pressure over 30 minutes, multiplying thevolume of fluid that goes through the filter by two, the composition canhave a fluid loss of less than about 40 mL, or about 20 mL to about 35mL, or 1 mL or less, or about 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13,14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31,32, 33, 34, 35, 36, 37, 38, 39, or about 40 mL or more.

Crosslinked Viscosifier Polymer.

The composition includes a crosslinked viscosifier polymer that includesan ethylene repeating unit including an —S(O)₂OR¹ group wherein at eachoccurrence R¹ is independently chosen from —H, substituted orunsubstituted (C₁-C₂₀)hydrocarbyl, and a counterion. The composition caninclude one crosslinked viscosifier polymer, or more than onecrosslinked viscosifier polymer. Any suitable concentration of the oneor more crosslinked viscosifier polymers can be present in thecomposition, such that the composition can be used as described herein.In some embodiments, about 0.01 wt % to about 100 wt % of thecomposition is the one or more crosslinked viscosifier polymers, orabout 0.1 wt % to about 50 wt %, about 0.1 wt % to about 10 wt %, orabout 0.001 wt % or less, or about 0.01 wt %, 0.05, 0.1, 0.2, 0.3, 0.4,0.5, 0.6, 0.7, 0.8, 0.9, 1, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9,2, 2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9, 3, 3.2, 3.4, 3.6, 3.8,4, 4.5, 5, 6, 7, 8, 9, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65,70, 75, 80, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99,99.9, 99.99, or about 99.999 wt % or more of the composition is the oneor more crosslinked viscosifier polymers.

The crosslinked viscosifier polymer can be sufficient to provideeffective increased viscosity to an aqueous liquid (e.g., to thecomposition) at various high temperatures. For example, the crosslinkedviscosifier polymer can provide effective increased viscosity at up toabout 500° F., or up to about 490° F., 480, 470, 460, 450, 440, 430,420, 410, 400, 390, 380, 370, 360, 350, 340, 330, 320, 310, 300, 290,280, 270, 260, 250, 240, 230, 220, 210, or up to about 200° F.

The crosslinked viscosifier polymer can have any suitable molecularweight, such as about 10,000 g/mol to about 50,000,000 g/mol, about100,000 g/mol to about 10,000,000 g/mol, or about 10,000 g/mol or less,or about 20,000 g/mol, 25,000, 50,000, 100,000, 150,000, 200,000,250,000, 500,000, 750,000, 1 million, 1.5 million, 2, 3, 4, 5, 6, 7, 8,9, 10, 11, 12, 13, 14, 15, 20, or 50 million g/mol or more. Thecrosslinked viscosifier polymer can have a molecular weight of at leastabout 1,000,000 g/mol, 5,000,000, 10,000,000, 20,000,000, or at leastabout 50,000,000 g/mol.

The crosslinked viscosifier polymer can have about A^(mol) mol % of therepeating unit including the —S(O)₂OR¹. The variable A^(mol) can beabout 30 mol % to about 99 mol %, or about 80 mol % to about 99 mol %,or about 30 mol % or less, or about 32, 34, 36, 38, 40, 42, 44, 46, 48,50, 52, 54, 56, 58, 60, 62, 64, 66, 68, 70, 72, 74, 76, 78, 80, 82, 84,86, 88, 90, 92, 94, 95, 96, 97, 98, or 99 mol % or more.

The crosslinked viscosifier polymer can include repeating units havingthe structure:

The repeating units can be in a block, alternate, or randomconfiguration, and each repeating unit is independently in theorientation shown or in the opposite orientation. At each occurrenceR^(A), R^(B), and R^(C) can be independently selected from the groupconsisting of —H and a substituted or unsubstituted (C₁-C₅)hydrocarbyl.At each occurrence L¹ can be independently selected from the groupconsisting of a bond and a substituted or unsubstituted(C₁-C₄₀)hydrocarbyl interrupted or terminated with 0, 1, 2, or 3 of atleast one of —S—, —O—, and substituted or unsubstituted —NH—. Thevariable a can have any value consistent with A^(mol) and the molecularweight of the crosslinked viscosifier polymer, such as about 2 to about10,000,000, about 10 to about 500,000, or about 2, 3, 4, 5, 6, 8, 10,12, 14, 16, 18, 20, 25, 30, 40, 50, 75, 100, 125, 150, 175, 200, 225,250, 300, 400, 500, 750, 1,000, 1,250, 1,500, 2,000, 2,500, 5,000,10,000, 15,000, 20,000, 25,000, 50,000, 75,000, 100,000, 150,000,200,000, 250,000, 500,000, 750,000, 1,000,000, 5,000,000, or about10,000,000 or more.

At each occurrence R¹ can be independently chosen from —H, substitutedor unsubstituted (C₁-C₂₀)hydrocarbyl, and a counterion. At eachoccurrence R¹ can be independently selected from the group consisting of—H, Na⁺, K⁺, Li⁺, NH₄ ⁺, Zn⁺, Ca²⁺, Zn²⁺, Al³⁺, Mg²⁺, and an organicamine cation such as NR^(E) ₄ ⁺, wherein at each occurrence R^(E) isindependently chosen from —H and substituted or unsubstituted(C₁-C₃₀)hydrocarbyl interrupted by 0, 1, 2, or 3 groups independentlychosen from —O—, —S—, and substituted or unsubstituted —NH—, or whereintwo or three R^(E) groups together form a substituted or unsubstituted(C₁-C₃₀)hydrocarbylene or (C₁-C₃₀)hydrocarbtriyl interrupted by 0, 1, 2,or 3 groups independently chosen from —O—, —S—, and substituted orunsubstituted —NH— (e.g., the nitrogen of NR^(E) ₄ ⁺ can be in the formof a nitrogen-containing heterocyclic ring as —N⁺R^(E) ₂— or as═N⁺R^(E)—). At each occurrence R¹ can be independently chosen from(C₁-C₂₀)alkyl, (C₁-C₁₀)alkyl, (C₁-C₅)alkyl, methyl, ethyl, propyl, andbutyl. At each occurrence R¹ can be —H.

At each occurrence R^(A), R^(B), and R^(C) can be independently selectedfrom the group consisting of —H and a substituted or unsubstituted(C₁-C₅)hydrocarbyl. At each occurrence R^(A), R^(B), and R^(C) can beindependently selected from the group consisting of —H and a(C₁-C₅)alkyl. At each occurrence R^(A), R^(B), and R^(C) can beindependently selected from the group consisting of —H and a(C₁-C₃)alkyl. At each occurrence R^(A), R^(B), and R^(C) can each be —H.

At each occurrence L¹ can be independently selected from the groupconsisting of a bond and a substituted or unsubstituted(C₁-C₄₀)hydrocarbyl interrupted or terminated with 0, 1, 2, or 3 of atleast one of —S—, —O—, and substituted or unsubstituted —NH—. At eachoccurrence L¹ can be independently selected from the group consisting ofa bond and -(substituted or unsubstituted(C₁-C₂₀)hydrocarbyl)-NR³-(substituted or unsubstituted(C₁-C₂₀)hydrocarbyl)-. At each occurrence L1 can be a —(C₅-C₂₀)aryl-. Ateach occurrence L¹ can be independently —C(O)—NH—(substituted orunsubstituted (C₁-C₂₀)hydrocarbyl)-. At each occurrence L¹ can beindependently —C(O)—NH—((C₁-C₅)hydrocarbyl)-. At each occurrence L¹ canbe —C(O)—NH—CH(CH₃)₂—CH₂—. The ethylene repeating unit including the—S(O)₂OR¹ group can be a 2-acrylamido-2-methylpropanesulfonic acid(AMPS) repeating unit (e.g., polymerized from, or formed bypolymerization of AMPS) or a salt or (C₁-C₅)alkyl ester thereof. Theethylene repeating unit including the —S(O)₂OR¹ group can be avinylbenzene sulfonate (e.g., 1,4-vinylbenezene sulfonate) or a salt or(C₁-C₅)alkyl ester thereof.

In various embodiments, in addition to the ethylene repeating unitincluding the —S(O)₂OR¹ group, the crosslinked viscosifier polymer canalso include a comonomer b that is an ethylene repeating unit includingat least one of a —OR^(D) group, a —O—C(O)—R^(D) group, a —C(O)—NH₂group, a —C(O)—NHR^(D) group, a —C(O)—NR^(D) ₂ group, a —C(O)—OH groupor a salt thereof, a —C(O)—OR^(D) group, a —NR^(D)—C(O)—R^(D) group, anda —(C₁₋₂₀)heterocyclyl, wherein the —(C₁₋₂₀)heterocyclyl is anitrogen-containing heterocycle substituent bound to the ethylenerepeating unit (e.g., directly or indirectly) via a nitrogen atom in theheterocyclic ring, and wherein R^(D) at each occurrence is independentlyselected from —H and substituted or unsubstituted (C₁-C₅₀)hydrocarbylinterrupted by 0, 1, 2, or 3 groups independently selected from —O—,—S—, and substituted or unsubstituted —NH—. The comonomer b can be anethylene repeating unit including at least one of a —C(O)—NH₂ group, a—C(O)—OH group or a salt or (C₁-C₅) alkyl ester thereof, a —C(O)—OR^(D)group, and —N-pyrrolidinyl. The comonomer b can be a repeating unitchosen from acrylamide, methacrylamide, acrylic acid, methacrylic acid,N-vinyl lactam, an N-vinylamide, N-vinylpyrrolidone, an acrylate ester,a methacrylate ester, and an N-substituted acrylamide, (e.g., whereinany one of the foregoing materials can polymerize with the materialincluding the S(O)₂OR¹ group, such as AMPS, in addition to thecrosslinker, to form the crosslinked viscosifier polymer). Thecrosslinked viscosifier polymer can have about B^(mol) mol % of thecomonomer b. The variable B^(mol) can be about 0 mol % to about 70 mol%, about 1 mol % to about 20 mol %, or about 0 mol %, 1, 2, 3, 4, 5, 6,7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 22, 24, 26, 28, 30,32, 34, 36, 38, 40, 42, 44, 46, 48, 50, 52, 54, 56, 58, 60, 62, 64, 66,68, or about 70 mol % or more. In various embodiments, B^(mol) can beless than 20 mol %, or less than 15 mol %, such as in embodimentsincluding comonomers that can hydrolyze, such as to acrylates ormethacrylates, under the desired conditions of use, such as attemperatures of about 400° F. In various embodiments, comonomers thatare more hydrolytically stable, such as N-vinyl lactams and N-vinylamides, can be used at greater than 20 mol %.

In various embodiments, the crosslinked viscosifier polymer includesrepeating units having the structure:

The repeating units can be in a block, alternate, or randomconfiguration, and each repeating unit is independently in theorientation shown or in the opposite orientation. At each occurrenceR^(A), R^(B), and R^(C) can be independently selected from the groupconsisting of —H and a substituted or unsubstituted (C₁-C₅)hydrocarbyl.At each occurrence L¹ and L² can be each independently selected from thegroup consisting of a bond and a substituted or unsubstituted(C₁-C₄₀)hydrocarbyl interrupted or terminated with 0, 1, 2, or 3 of atleast one of —S—, —O—, and substituted or unsubstituted —NH—. At eachoccurrence Z can be independently chosen from a —OR^(D) group, a—O—C(O)—R^(D) group, a —C(O)—NH₂ group, a —C(O)—NHR^(D) group, a—C(O)—NR^(D) ₂ group, a —C(O)—OH group or a salt thereof, a —C(O)—OR^(D)group, a —NR^(D)—C(O)—R^(D) group, and a —(C₁₋₂₀)heterocyclyl, whereinthe —(C₁₋₂₀)heterocyclyl is a nitrogen-containing heterocyclesubstituent bound to the ethylene repeating unit via a nitrogen atom inthe heterocyclic ring, and wherein R^(D) at each occurrence isindependently selected from —H and substituted or unsubstituted(C₁-C₅₀)hydrocarbyl interrupted by 0, 1, 2, or 3 groups independentlyselected from —O—, —S—, and substituted or unsubstituted —NH—. Thevariable b can have any value consistent with B^(mol) and the molecularweight of the crosslinked viscosifier polymer, such as about 0 to about1,000,000, about 5 to about 100,000, or about 0, 1, 2, 3, 4, 5, 6, 8,10, 12, 14, 16, 18, 20, 25, 30, 40, 50, 75, 100, 125, 150, 175, 200,225, 250, 300, 400, 500, 750, 1,000, 1,250, 1,500, 2,000, 2,500, 5,000,10,000, 15,000, 20,000, 25,000, 30,000, 40,000, 50,000, 60,000, 70,000,80,000, 90,000, or about 100,000 or more.

The variable R^(D) at each occurrence can be independently selected from—H and substituted or unsubstituted (C₁-C₅₀)hydrocarbyl interrupted by0, 1, 2, or 3 groups independently selected from —O—, —S—, andsubstituted or unsubstituted —NH—. The variable R^(D) at each occurrencecan be independently selected from —H and substituted or unsubstituted(C₁-C₁₀)hydrocarbyl. The variable R^(D) at each occurrence can beindependently selected from —H and substituted or unsubstituted(C₁-C₁₀)alkyl.

At each occurrence the variable L² can be independently selected fromthe group consisting of a bond and a substituted or unsubstituted(C₁-C₄₀)hydrocarbyl interrupted or terminated with 0, 1, 2, or 3 of atleast one of —S—, —O—, and substituted or unsubstituted —NH—. At eachoccurrence the variable L² can be independently selected from a bond anda (C₁-C₂₀)hydrocarbyl. At each occurrence L² can be independentlyselected from a bond and a (C₁-C₅)alkyl. At each occurrence L² can be abond.

In addition to the ethylene repeating unit including the —S(O)₂OR¹group, the crosslinked viscosifier polymer also includes a crosslinkermonomer unit (e.g., comonomer c). The crosslinker used to crosslink thecrosslinked viscosifier polymer can be any suitable polyalkenylcrosslinker. For example, the crosslinked viscosifier can be crosslinkedvia at least one of a (C₁-C₂₀)alkylenebiacrylamide (e.g.,methylenebisacrylamide), a poly((C₁-C₂₀)alkenyl)-substituted mono- orpoly-(C₁-C₂₀)alkyl ether (e.g., pentaerythritol allyl ether), and apoly(C₂-C₂₀)alkenylbenzene (e.g., divinylbenzene). In some embodiments,the crosslinked viscosifier can be crosslinked via at least onecrosslinker chosen from methylenebisacrylamide, ethylenebisacrylamide, apolyethylene glycol dimethacrylate, 1,1,1-trimethylolpropanetrimethacrylate, divinyl ether, diallyl ether, a vinyl or allyl ether ofa polyglycol or a polyol, N,N′-divinylethyleneurea, a divinylbenzene,divinyltetrahydropyrimidin-2(1H)-one, a diene, an allyl amine,N-vinyl-3(E)-ethylidene pyrrolidone, ethylidene bis(N-vinylpyrrolidone),allyl acrylate, N,N-diallylacrylamide, 2,4,6-triallyloxy-1,3,5-triazine,1,3,5-triacryloylhexahydro-1,3,5-triazine, ethylene glycol diacrylate,ethylene glycol dimethacrylate, polyethylene glycol diacrylate,polyethylene glycol dimethacrylate, ethoxylated bisphenol A diacrylate,ethoxylated bisphenol A dimethacrylate, ethoxylated trimethylol propanetriacrylate, ethoxylated trimethylol propane trimethacrylate,ethoxylated glyceryl triacrylate, ethoxylated glyceryl trimethacrylate,pentaerythritol allyl ether, ethoxylated pentaerythritol tetraacrylate,ethoxylated pentaerythritol tetramethacrylate, ethoxylateddipentaerythritol hexaacrylate, polyglyceryl monoethylene oxidepolyacrylate, polyglyceryl polyethylene glycol polyacrylate,dipentaerythritol hexaacrylate, dipentaerythritol hexamethacrylate,neopentyl glycol diacrylate, neopentyl glycol dimethacrylate,pentaerythritol triacrylate, pentaerythritol trimethacrylate,trimethylol propane triacrylate, trimethylol propane trimethacrylate,tricyclodecane dimethanol diacrylate, tricyclodecane dimethanoldimethacrylate, 1,6-hexanediol diacrylate, and 1,6-hexanedioldimethacrylate.

The crosslinker in the crosslinked viscosifier polymer can be anethylene repeating unit including a crosslinking group L^(CL), whereinL^(CL) can correspond to the inter- or intra-molecular linking groupformed by forming the crosslinked viscosifier polymer using any suitablecrosslinker described herein. For example, at each occurrence L^(CL) canbe independently a -(substituted or unsubstituted(C₁-C₄₀)hydrocarbylene)-M, wherein the (C₁-C₄₀)hydrocarbylene issubstituted or unsubstituted and is interrupted by 0, 1, 2, or 3 groupsindependently selected from —O—, —S—, substituted or unsubstituted —NH—,and —((C₂-C₅)alkoxy)_(n1)—wherein at each occurrence M is independentlyan ethylene repeating unit of the same crosslinked viscosifier polymermolecule or an ethylene repeating unit of another molecule of thecrosslinked viscosifier polymer, wherein n1 is about 2 to about 10,000(e.g., about 2, 3, 4, 5, 6, 8, 10, 12, 14, 16, 18, 20, 25, 30, 40, 50,75, 100, 150, 200, 250, 500, 1,000, 1,250, 1,500, 2,000, 2,500, 5,000,7,500, or about 10,000 or more). The crosslinked viscosifier polymer canhave about C^(mol) mol % of the crosslinker. The variable C^(mol) can beabout 0.01 mol % to about 30 mol %, about 0.1 mol % to about 10 mol %,or about 0.01 mol % or less, or about 0.05 mol %, 0.1, 0.2, 0.3, 0.4,0.5, 0.6, 0.7, 0.8, 0.9, 1.0, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8,1.9, 2.0, 2.2, 2.4, 2.6, 2.8, 3.0, 3.2, 3.4, 3.6, 3.8, 4.0, 4.2, 4.4,4.6, 4.8, 5.0, 5.5, 6.0, 6.5, 7.0, 7.5, 8.0, 9, 10, 11, 12, 13, 14, 15,16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, or about 30 mol% or more.

The crosslinked viscosifier polymer can include repeating units havingthe structure:

The repeating units can be in a block, alternate, or randomconfiguration, and each repeating unit is independently in theorientation shown or in the opposite orientation. At each occurrenceR^(A), R^(B), and R^(C) can be independently selected from the groupconsisting of —H and a substituted or unsubstituted (C₁-C₅)hydrocarbyl.At each occurrence L¹ can be independently selected from the groupconsisting of a bond and a substituted or unsubstituted(C₁-C₄₀)hydrocarbyl interrupted or terminated with 0, 1, 2, or 3 of atleast one of —S—, —O—, and substituted or unsubstituted —NH—. At eachoccurrence L^(CL) can be independently chosen from a—((C₁-C₁₀)heterocyclylene)- and a -(substituted or unsubstituted(C₁-C₄₀)hydrocarbylene)-M, wherein the (C₁-C₄₀)hydrocarbylene issubstituted or unsubstituted and is interrupted by 0, 1, 2, or 3 groupsindependently selected from —O—, —S—, substituted or unsubstituted —NH—,and —((C₂-C₅)alkoxy)_(n1)-, wherein at each occurrence M isindependently an ethylene repeating unit of the same crosslinkedviscosifier polymer molecule or an ethylene repeating unit of anothermolecule of the crosslinked viscosifier polymer, wherein n1 is about 2to about 10,000. At each occurrence L^(CL) can be independently chosenfrom —C(O)—NH—R^(CL1)—NH—C(O)-M, —C(O)—(O—R^(CL1))_(n2)—O—C(O)-M,—C(O)—O—CR^(CL2)(O—C(O)-M)₂, —R^(CL1)—O—R^(CL1)—C(—R^(CL1)—O—R^(CL3))₃,—O-M, —R^(CL1)—O—R^(CL1)-M, —R^(CL1)—O-M, —O—R^(CL1)-M, N,N-boundtetrahydropyrimidin-2(1H)-one, N,3-bound pyrrolidone, 1,3-bound2-imidazolidone, and N,N-bound pyrrolidone-R^(CL1) -pyrrolidone whereinthe pyrrolidones are bound to R^(CL1) via the 3-positions, whereinR^(CL1) is a substituted or unsubstituted (C₁-C₄₀)hydrocarbylene,R^(CL2) is chosen from H and a substituted or unsubstituted(C₁-C₄₀)hydrocarbylene, R^(CL3) is R^(CL2) or-R^(CL1)-M, and R^(CL1) andR^(CL2) are interrupted by 0, 1, 2, or 3 groups independently chosenfrom —O—, —S—, and substituted or unsubstituted —NH, and n2 can be about0 to about 10,000 (e.g., about 2, 3, 4, 5, 6, 8, 10, 12, 14, 16, 18, 20,25, 30, 40, 50, 75, 100, 150, 200, 250, 500, 1,000, 1,250, 1,500, 2,000,2,500, 5,000, 7,500, or about 10,000 or more). At each occurrence L^(CL)can be independently chosen from —C(O)—NH—CH₂—NH—C(O)-M,—C(O)—NH—CH₂—CH₂—NH—C(O)-M, —C(O)—(O—CH₂—CH₂)_(n2)—O—C(O)-M,—C(O)—(O—CH₂—CH₂—CH₂)_(n2)—O—C(O)-M, —C(O)—O—C(CH₂—CH₃)(O—C(O)-M)₂,—CH₂—O—CH₂—C(—CH₂—O—R^(CL3))₃, —O-M, —CH₂—O—CH₂-M, —CH₂—O-M, —O—CH₂-M,N,N-bound tetrahydropyrimidin-2(1H)-one, N,3-bound pyrrolidone,1,3-bound 2-imidazolidone, and N,N-bound pyrrolidone-R^(CL1)-pyrrolidonewherein the pyrrolidones are bound to R^(CL1) via the 3-positions,wherein R^(CL3) at each occurrence is —CH₂-M or H. In repeating unitsthat include multiple R^(CL3) moieties, the repeating units can have anaverage of about 1, 2, or 3 or more R^(CL3) that are —R^(CL1)-M or—CH₂-M. The variable c can have any value consistent with C^(mol) andthe molecular weight of the crosslinked viscosifier polymer, such asabout 1 to about 1,000,000, about 5 to about 100,000, or about 1, 2, 3,4, 5, 6, 8, 10, 12, 14, 16, 18, 20, 25, 30, 40, 50, 75, 100, 125, 150,175, 200, 225, 250, 300, 400, 500, 750, 1,000, 1,250, 1,500, 2,000,2,500, 5,000, 10,000, 15,000, 20,000, 25,000, 30,000, 40,000, 50,000,60,000, 70,000, 80,000, 90,000, 100,000, 250,000, 500,000, 750,000, orabout 1,000,000 or more.

At each occurrence, R^(CL1) can be independently a substituted orunsubstituted (C₁-C₄₀)hydrocarbylene. At each occurrence, R^(CL1) can beindependently chosen from a (C₁-C₂₀)alkylene, (C₁-C₁₀)alkylene,(C₁-C₅)alkylene, methylene, ethylene, propylene, and butylene.

At each occurrence R^(CL2) can be chosen from H and a substituted orunsubstituted (C₁-C₄₀)hydrocarbylene. At each occurrence, R^(CL2) can beindependently chosen from a (C₁-C₂₀)alkyl, (C₁-C₁₀)alkyl, (C₁-C₅)alkyl,methyl, ethyl, propyl, butyl, and —H.

In some embodiments, the crosslinked viscosifier polymer includesrepeating units having the structure:

The repeating units can be in a block, alternate, or randomconfiguration, and each repeating unit is independently in theorientation shown or in the opposite orientation. At each occurrenceR^(A), R^(B), and R^(C) can be independently selected from the groupconsisting of —H and a substituted or unsubstituted (C₁-C₅)hydrocarbyl.At each occurrence L¹ and L² can each independently be selected from thegroup consisting of a bond and a substituted or unsubstituted(C₁-C₄₀)hydrocarbyl interrupted or terminated with 0, 1, 2, or 3 of atleast one of —S—, —O—, and substituted or unsubstituted —NH—. Thevariable Z at each occurrence can be independently chosen from a —OR^(D)group, a —O—C(O)—R^(D) group, a —C(O)—NH₂ group, a —C(O)—NHR^(D) group,a —C(O)—NR^(D) ₂ group, a —C(O)—OH group or a salt thereof, a—C(O)—OR^(D) group, a —NR^(D)—C(O)—R^(D) group, and a—(C₁₋₂₀)heterocyclyl, wherein the —(C₁₋₂₀)heterocyclyl is anitrogen-containing heterocycle substituent bound to the ethylenerepeating unit via a nitrogen atom in the heterocyclic ring, and whereinR^(D) at each occurrence is independently selected from —H andsubstituted or unsubstituted (C₁-C₅₀)hydrocarbyl interrupted by 0, 1, 2,or 3 groups independently selected from —O—, —S—, and substituted orunsubstituted —NH—. At each occurrence L^(CL) is independently chosenfrom a —((C₁-C₁₀)heterocyclylene)- and a -(substituted or unsubstituted(C₁-C₄₀)hydrocarbylene)-M, wherein the (C₁-C₄₀)hydrocarbylene issubstituted or unsubstituted and is interrupted by 0, 1, 2, or 3 groupsindependently selected from —O—, —S—, substituted or unsubstituted —NH—,and —((C₂-C₅)alkoxy)_(n)-, wherein at each occurrence M is independentlyan ethylene repeating unit of the same crosslinked viscosifier polymermolecule or an ethylene repeating unit of another molecule of thecrosslinked viscosifier polymer. The crosslinked viscosifier polymer canhave about A^(mol) mol % of the repeating unit including the —S(O)₂OR¹,wherein A^(mol) is about 30 mol % to about 99 mol %. The crosslinkedviscosifier polymer can have about B^(mol) mol % of the comonomer b,wherein B^(mol) is about 0 mol % to about 70 mol %. The crosslinkedviscosifier polymer can have about C^(mol) mol % of the comonomer c,wherein C^(mol) is about 0.01 mol % to about 30 mol %, whereinA^(mol)+B^(mol)+C^(mol) is about 100 mol %.

The crosslinked viscosifier polymer can include repeating units havingthe structure:

The repeating units can be in a block, alternate, or randomconfiguration, and each repeating unit is independently in theorientation shown or in the opposite orientation. At each occurrenceR^(A), R^(B), and R^(C) can be independently selected from the groupconsisting of —H and (C₁-C₅)alkyl. At each occurrence Z can beindependently chosen from an —OH group, a —OR^(D) group, a —O—C(O)—R^(D)group, a —C(O)—NH₂ group, a —C(O)—OH group or a salt or (C₁-C₅) alkylester thereof, a —C(O)—OR^(D) group, and —N-pyrrolidinyl, wherein R^(D)at each occurrence is independently (C₁-C₅)alkyl. At each occurrenceL^(CL) can be independently chosen from —C(O)—NH—CH₂—NH—C(O)-M,—C(O)—NH—CH₂—CH₂—NH—C(O)-M, —C(O)—(O—CH₂—CH₂)_(n2)—O—C(O)-M,—C(O)—(O—CH₂—CH₂—CH₂)_(n2)—O—C(O)-M, —C(O)—O—C(CH₂—CH₃)(O—C(O)-M)₂,—CH₂—O—CH₂—C(—CH₂—O—R^(CL3))₃, —O-M, —CH₂—O—CH₂-M, —CH₂—O-M, —O—CH₂-M,N,N-bound tetrahydropyrimidin-2(1H)-one, N,3-bound pyrrolidone,1,3-bound 2-imidazolidone, and N,N-bound pyrrolidone-R^(CL1)-pyrrolidonewherein the pyrrolidones are bound to R^(CL1) via the 3-positions,wherein R^(CL3) at each occurrence is —CH₂-M or H, wherein at eachoccurrence M is independently an ethylene repeating unit of the samecrosslinked viscosifier polymer molecule or an ethylene repeating unitof another molecule of the crosslinked viscosifier polymer. Thecrosslinked viscosifier polymer can have about A^(mol) mol % of therepeating unit including the —S(O)₂OR¹, wherein A^(mol) is about 30 mol% to about 99 mol %. The crosslinked viscosifier polymer can have aboutB^(mol) mol % of the comonomer b, wherein B^(mol) is about 0 mol % toabout 70 mol %. The crosslinked viscosifier polymer can have aboutC^(mol) mol % of the comonomer c, wherein C^(mol) is about 0.01 mol % toabout 30 mol %, wherein A^(mol)+B^(mol)+C^(mol) is about 100 mol %.

In various embodiments, salts of acids (e.g., of carboxylic acids orsulfonic acids) can include any suitable positively charged counterion.For example, the counterion can be ammonium(NH₄ ⁺), or an alkali metalsuch as sodium (Na+), potassium (K⁺), or lithium (Li⁺). In someembodiments, the counterion can have a positive charge greater than +1,which can in some embodiments complex to multiple ionized groups, suchas Zn²⁺, Al³⁺, or alkaline earth metals such as Ca²⁺ or Mg²⁺.

The polymers described herein can terminate in any suitable way. In someembodiments, the polymers can terminate with an end group that isindependently chosen from a suitable polymerization initiator, —H, —OH,a substituted or unsubstituted (C₁-C₂₀)hydrocarbyl (e.g., (C₁-C₁₀)alkylor (C₆-C₂₀)aryl) interrupted with 0, 1, 2, or 3 groups independentlyselected from —O—, substituted or unsubstituted —NH—, and —S—, apoly(substituted or unsubstituted (C₁-C₂₀)hydrocarbyloxy), and apoly(substituted or unsubstituted (C₁-C₂₀)hydrocarbylamino).

Other Components.

The composition including the crosslinked viscosifier polymer, or amixture including the composition, can include any suitable additionalcomponent in any suitable proportion, such that the crosslinkedviscosifier polymer, composition, or mixture including the same, can beused as described herein.

The composition can further include a secondary viscosifier, in additionto the crosslinked viscosifier polymer. The secondary viscosifier canaffect the viscosity of the composition or a solvent that contacts thecomposition at any suitable time and location. In some embodiments, thesecondary viscosifier provides an increased viscosity at least one ofbefore injection into the subterranean formation, at the time ofinjection into the subterranean formation, during travel through atubular disposed in a borehole, once the composition reaches aparticular subterranean location, or some period of time after thecomposition reaches a particular subterranean location. In someembodiments, the secondary viscosifier can be about 0.000,1 wt % toabout 10 wt % of the composition or a mixture including the same, about0.004 wt % to about 0.01 wt %, or about 0.000,1 wt % or less, 0.000,5 wt%, 0.001, 0.005, 0.01, 0.05, 0.1, 0.5, 1, 2, 3, 4, 5, 6, 7, 8, 9, orabout 10 wt % or more of the composition or a mixture including thesame.

The secondary viscosifier can include at least one of a substituted orunsubstituted polysaccharide, and a substituted or unsubstitutedpolyalkene (e.g., a polyethylene, wherein the ethylene unit issubstituted or unsubstituted, derived from the corresponding substitutedor unsubstituted ethene), wherein the polysaccharide or polyalkene iscrosslinked or uncrosslinked. The secondary viscosifier can include apolymer including at least one repeating unit derived from a monomerselected from the group consisting of ethylene glycol, acrylamide, vinylacetate, 2-acrylamidomethylpropane sulfonic acid or its salts,trimethylammoniumethyl acrylate halide, and trimethylammoniumethylmethacrylate halide. The secondary viscosifier can include a crosslinkedgel or a crosslinkable gel. The secondary viscosifier can include atleast one of a linear polysaccharide, and a poly((C₂-C₁₀)alkene),wherein the (C₂-C₁₀)alkene is substituted or unsubstituted. Thesecondary viscosifier can include at least one of poly(acrylic acid) or(C₁-C₅)alkyl esters thereof, poly(methacrylic acid) or (C₁-C₅)alkylesters thereof, poly(vinyl acetate), poly(vinyl alcohol), poly(ethyleneglycol), poly(vinyl pyrrolidone), polyacrylamide, poly (hydroxyethylmethacrylate), alginate, chitosan, curdlan, dextran, derivatizeddextran, emulsan, a galactoglucopolysaccharide, gellan, glucuronan,N-acetyl-glucosamine, N-acetyl-heparosan, hyaluronic acid, kefiran,lentinan, levan, mauran, pullulan, scleroglucan, schizophyllan,stewartan, succinoglycan, xanthan, diutan, welan, starch, derivatizedstarch, tamarind, tragacanth, guar gum, derivatized guar gum (e.g.,hydroxypropyl guar, carboxy methyl guar, or carboxymethyl hydroxypropylguar), gum ghatti, gum arabic, locust bean gum, cellulose, andderivatized cellulose (e.g., carboxymethyl cellulose, hydroxyethylcellulose, carboxymethyl hydroxyethyl cellulose, hydroxypropylcellulose, or methyl hydroxy ethyl cellulose).

In some embodiments, the secondary viscosifier can include at least oneof a poly(vinyl alcohol) homopolymer, poly(vinyl alcohol) copolymer, acrosslinked poly(vinyl alcohol) homopolymer, and a crosslinkedpoly(vinyl alcohol) copolymer. The secondary viscosifier can include apoly(vinyl alcohol) copolymer or a crosslinked poly(vinyl alcohol)copolymer including at least one of a graft, linear, branched, block,and random copolymer of vinyl alcohol and at least one of a substitutedor unsubstituted (C₂-C₅₀)hydrocarbyl having at least one aliphaticunsaturated C—C bond therein, and a substituted or unsubstituted(C₂-C₅₀)alkene. The secondary viscosifier can include a poly(vinylalcohol) copolymer or a crosslinked poly(vinyl alcohol) copolymerincluding at least one of a graft, linear, branched, block, and randomcopolymer of vinyl alcohol and at least one of vinyl phosphonic acid,vinylidene diphosphonic acid, substituted or unsubstituted2-acrylamido-2-methylpropanesulfonic acid, a substituted orunsubstituted (C₁-C₂₀)alkenoic acid, propenoic acid, butenoic acid,pentenoic acid, hexenoic acid, octenoic acid, nonenoic acid, decenoicacid, acrylic acid, methacrylic acid, hydroxypropyl acrylic acid,acrylamide, fumaric acid, methacrylic acid, hydroxypropyl acrylic acid,vinyl phosphonic acid, vinylidene diphosphonic acid, itaconic acid,crotonic acid, mesoconic acid, citraconic acid, styrene sulfonic acid,allyl sulfonic acid, methallyl sulfonic acid, vinyl sulfonic acid, and asubstituted or unsubstituted (C₁-C₂₀)alkyl ester thereof. The secondaryviscosifier can include a poly(vinyl alcohol) copolymer or a crosslinkedpoly(vinyl alcohol) copolymer including at least one of a graft, linear,branched, block, and random copolymer of vinyl alcohol and at least oneof vinyl acetate, vinyl propanoate, vinyl butanoate, vinyl pentanoate,vinyl hexanoate, vinyl 2-methyl butanoate, vinyl 3-ethylpentanoate, andvinyl 3-ethylhexanoate, maleic anhydride, a substituted or unsubstituted(C₁-C₂₀)alkenoic substituted or unsubstituted (C₁-C₂₀)alkanoicanhydride, a substituted or unsubstituted (C₁-C₂₀)alkenoic substitutedor unsubstituted (C₁-C₂₀)alkenoic anhydride, propenoic acid anhydride,butenoic acid anhydride, pentenoic acid anhydride, hexenoic acidanhydride, octenoic acid anhydride, nonenoic acid anhydride, decenoicacid anhydride, acrylic acid anhydride, fumaric acid anhydride,methacrylic acid anhydride, hydroxypropyl acrylic acid anhydride, vinylphosphonic acid anhydride, vinylidene diphosphonic acid anhydride,itaconic acid anhydride, crotonic acid anhydride, mesoconic acidanhydride, citraconic acid anhydride, styrene sulfonic acid anhydride,allyl sulfonic acid anhydride, methallyl sulfonic acid anhydride, vinylsulfonic acid anhydride, and an N—(C₁-C₁₀)alkenyl nitrogen containingsubstituted or unsubstituted (C₁-C₁₀)heterocycle. The secondaryviscosifier can include a poly(vinyl alcohol) copolymer or a crosslinkedpoly(vinyl alcohol) copolymer including at least one of a graft, linear,branched, block, and random copolymer that includes apoly(vinylalcohol/acrylamide) copolymer, apoly(vinylalcohol/2-acrylamido-2-methylpropanesulfonic acid) copolymer,a poly (acrylamide/2-acrylamido-2-methylpropanesulfonic acid) copolymer,or a poly(vinylalcohol/N-vinylpyrrolidone) copolymer. The secondaryviscosifier can include a crosslinked poly(vinyl alcohol) homopolymer orcopolymer including a crosslinker including at least one of chromium,aluminum, antimony, zirconium, titanium, calcium, boron, iron, silicon,copper, zinc, magnesium, and an ion thereof. The secondary viscosifiercan include a crosslinked poly(vinyl alcohol) homopolymer or copolymerincluding a crosslinker including at least one of an aldehyde, analdehyde-forming compound, a carboxylic acid or an ester thereof, asulfonic acid or an ester thereof, a phosphonic acid or an esterthereof, an acid anhydride, and an epihalohydrin.

In various embodiments, the composition can include one or morecrosslinkers. The crosslinker can be any suitable crosslinker. In someexamples, the crosslinker can be incorporated in a crosslinkedviscosifier, and in other examples, the crosslinker can crosslink acrosslinkable material (e.g., downhole). The crosslinker can include atleast one of chromium, aluminum, antimony, zirconium, titanium, calcium,boron, iron, silicon, copper, zinc, magnesium, and an ion thereof. Thecrosslinker can include at least one of boric acid, borax, a borate, a(C₁-C₃₀)hydrocarbylboronic acid, a (C₁-C₃₀)hydrocarbyl ester of a(C₁-C₃₀)hydrocarbylboronic acid, a (C₁-C₃₀)hydrocarbylboronicacid-modified polyacrylamide, ferric chloride, disodium octaboratetetrahydrate, sodium metaborate, sodium diborate, sodium tetraborate,disodium tetraborate, a pentaborate, ulexite, colemanite, magnesiumoxide, zirconium lactate, zirconium triethanol amine, zirconium lactatetriethanolamine, zirconium carbonate, zirconium acetylacetonate,zirconium malate, zirconium citrate, zirconium diisopropylamine lactate,zirconium glycolate, zirconium triethanol amine glycolate, zirconiumlactate glycolate, titanium lactate, titanium malate, titanium citrate,titanium ammonium lactate, titanium triethanolamine, titaniumacetylacetonate, aluminum lactate, and aluminum citrate. In someembodiments, the crosslinker can be a (C₁-C₂₀)alkylenebiacrylamide(e.g., methylenebisacrylamide), a poly((C₁-C₂₀)alkenyl)-substitutedmono- or poly-(C₁-C₂₀)alkyl ether (e.g., pentaerythritol allyl ether),and a poly(C₂-C₂₀)alkenylbenzene (e.g., divinylbenzene). In someembodiments, the crosslinker can be at least one of alkyl diacrylate,ethylene glycol diacrylate, ethylene glycol dimethacrylate, polyethyleneglycol diacrylate, polyethylene glycol dimethacrylate, ethoxylatedbisphenol A diacrylate, ethoxylated bisphenol A dimethacrylate,ethoxylated trimethylol propane triacrylate, ethoxylated trimethylolpropane trimethacrylate, ethoxylated glyceryl triacrylate, ethoxylatedglyceryl trimethacrylate, ethoxylated pentaerythritol tetraacrylate,ethoxylated pentaerythritol tetramethacrylate, ethoxylateddipentaerythritol hexaacrylate, polyglyceryl monoethylene oxidepolyacrylate, polyglyceryl polyethylene glycol polyacrylate,dipentaerythritol hexaacrylate, dipentaerythritol hexamethacrylate,neopentyl glycol diacrylate, neopentyl glycol dimethacrylate,pentaerythritol triacrylate, pentaerythritol trimethacrylate,trimethylol propane triacrylate, trimethylol propane trimethacrylate,tricyclodecane dimethanol diacrylate, tricyclodecane dimethanoldimethacrylate, 1,6-hexanediol diacrylate, and 1,6-hexanedioldimethacrylate. The crosslinker can be about 0.000,01 wt % to about 5 wt% of the composition or a mixture including the same, about 0.001 wt %to about 0.01 wt %, or about 0.000,01 wt % or less, or about 0.000.05 wt%, 0.000,1, 0.000,5, 0.001, 0.005, 0.01, 0.05, 0.1, 0.5, 1, 2, 3, 4, orabout 5 wt % or more.

In some embodiments, the composition can include one or more breakers.The breaker can be any suitable breaker, such that the surrounding fluid(e.g., a fracturing fluid) can be at least partially broken for morecomplete and more efficient recovery thereof, such as at the conclusionof the hydraulic fracturing treatment. In some embodiments, the breakercan be encapsulated or otherwise formulated to give a delayed-release ora time-release of the breaker, such that the surrounding liquid canremain viscous for a suitable amount of time prior to breaking. Thebreaker can be any suitable breaker; for example, the breaker can be acompound that includes a Na⁺, K⁺, Li⁺, Zn⁺, NH₄ ⁺, Fe²⁺, Fe³⁺, Cu¹⁺,Cu²⁺, Ca²⁺, Mg²⁺, Zn²⁺, and an Al³⁺ salt of a chloride, fluoride,bromide, phosphate, or sulfate ion. In some examples, the breaker can bean oxidative breaker or an enzymatic breaker. An oxidative breaker canbe at least one of a Na⁺, K⁺, Li⁺, Zn⁺, NH₄ ⁺, Fe²⁺, Fe³⁺, Cu¹⁺, Cu²⁺,Ca²⁺, Mg²⁺, Zn²⁺, and an Al³⁺ salt of a persulfate, percarbonate,perborate, peroxide, perphosphosphate, permanganate, chlorite, orhyporchlorite ion. An enzymatic breaker can be at least one of an alphaor beta amylase, amyloglucosidase, oligoglucosidase, invertase, maltase,cellulase, hemi-cellulase, and mannanohydrolase. The breaker can beabout 0.001 wt % to about 30 wt % of the composition or a mixtureincluding the same, or about 0.01 wt % to about 5 wt %, or about 0.001wt % or less, or about 0.005 wt %, 0.01, 0.05, 0.1, 0.5, 1, 2, 3, 4, 5,6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 26, 28, or about 30 wt % or more.

The composition, or a mixture including the composition, can include anysuitable fluid. For example, the fluid can be at least one of crude oil,dipropylene glycol methyl ether, dipropylene glycol dimethyl ether,dipropylene glycol methyl ether, dipropylene glycol dimethyl ether,dimethyl formamide, diethylene glycol methyl ether, ethylene glycolbutyl ether, diethylene glycol butyl ether, butylglycidyl ether,propylene carbonate, D-limonene, a C₂-C₄₀ fatty acid C₁-C₁₀ alkyl ester(e.g., a fatty acid methyl ester), tetrahydrofurfuryl methacrylate,tetrahydrofurfuryl acrylate, 2-butoxy ethanol, butyl acetate, butyllactate, furfuryl acetate, dimethyl sulfoxide, dimethyl formamide, apetroleum distillation product of fraction (e.g., diesel, kerosene,napthas, and the like) mineral oil, a hydrocarbon oil, a hydrocarbonincluding an aromatic carbon-carbon bond (e.g., benzene, toluene), ahydrocarbon including an alpha olefin, xylenes, an ionic liquid, methylethyl ketone, an ester of oxalic, maleic or succinic acid, methanol,ethanol, propanol (iso- or normal-), butyl alcohol (iso-, tert-, ornormal-), an aliphatic hydrocarbon (e.g., cyclohexanone, hexane), water,brine, produced water, flowback water, brackish water, and sea water.The fluid can form about 0.001 wt % to about 99.999 wt % of thecomposition, or a mixture including the same, or about 0.001 wt % orless, 0.01 wt %, 0.1, 1, 2, 3, 4, 5, 6, 8, 10, 15, 20, 25, 30, 35, 40,45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 96, 97, 98, 99, 99.9, 99.99,or about 99.999 wt % or more.

The composition including the crosslinked viscosifier polymer or amixture including the same can include any suitable downhole fluid. Thecomposition including the crosslinked viscosifier polymer can becombined with any suitable downhole fluid before, during, or after theplacement of the composition in the subterranean formation or thecontacting of the composition and the subterranean material. In someexamples, the composition including the crosslinked viscosifier polymeris combined with a downhole fluid above the surface, and then thecombined composition is placed in a subterranean formation or contactedwith a subterranean material. In another example, the compositionincluding the crosslinked viscosifier polymer is injected into asubterranean formation to combine with a downhole fluid, and thecombined composition is contacted with a subterranean material or isconsidered to be placed in the subterranean formation. The placement ofthe composition in the subterranean formation can include contacting thesubterranean material and the mixture. Any suitable weight percent ofthe composition or of a mixture including the same that is placed in thesubterranean formation or contacted with the subterranean material canbe the downhole fluid, such as about 0.001 wt % to about 99.999 wt %,about 0.01 wt % to about 99.99 wt %, about 0.1 wt % to about 99.9 wt %,about 20 wt % to about 90 wt %, or about 0.001 wt % or less, or about0.01 wt %, 0.1, 1, 2, 3, 4, 5, 10, 15, 20, 30, 40, 50, 60, 70, 80, 85,90, 91, 92, 93, 94, 95, 96, 97, 98, 99, 99.9, 99.99 wt %, or about99.999 wt % or more of the composition or mixture including the same.

In some embodiments, the composition, or a mixture including the same,can include any suitable amount of any suitable material used in adownhole fluid. For example, the composition or a mixture including thesame can include water, saline, aqueous base, acid, oil, organicsolvent, synthetic fluid oil phase, aqueous solution, alcohol or polyol,cellulose, starch, alkalinity control agents, acidity control agents,density control agents, density modifiers, emulsifiers, dispersants,polymeric stabilizers, crosslinking agents, polyacrylamide, a polymer orcombination of polymers, antioxidants, heat stabilizers, foam controlagents, solvents, diluents, plasticizer, filler or inorganic particle,pigment, dye, precipitating agent, oil-wetting agents, set retardingadditives, surfactants, gases, weight reducing additives, heavy-weightadditives, lost circulation materials, filtration control additives,salts (e.g., any suitable salt, such as potassium salts such aspotassium chloride, potassium bromide, potassium formate; calcium saltssuch as calcium chloride, calcium bromide, calcium formate; cesium saltssuch as cesium chloride, cesium bromide, cesium formate, or acombination thereof), fibers, thixotropic additives, breakers,crosslinkers, rheology modifiers, curing accelerators, curing retarders,pH modifiers, chelating agents, scale inhibitors, enzymes, resins, watercontrol materials, oxidizers, markers, Portland cement, pozzolanacement, gypsum cement, high alumina content cement, slag cement, silicacement, fly ash, metakaolin, shale, zeolite, a crystalline silicacompound, amorphous silica, hydratable clays, microspheres, lime, or acombination thereof. In various embodiments, the composition or amixture including the same can include one or more additive componentssuch as: COLDTROL®, ATC®, OMC 2™, and OMC 42™ thinner additives; RHEMOD™viscosifier and suspension agent; TEMPERUS™ and VIS-PLUS® additives forproviding temporary increased viscosity; TAU-MOD™viscosifying/suspension agent; ADAPTA®, DURATONE® HT, THERMO TONE™,BDF™-366, and BDF™-454 filtration control agents; LIQUITONE™ polymericfiltration agent and viscosifier; FACTANT™ emulsion stabilizer; LESUPERMUL™, EZ MUL® NT, and FORTI-MUL® emulsifiers; DRIL TREAT® oilwetting agent for heavy fluids; AQUATONE-S™ wetting agent; BARACARB®bridging agent; BAROID® weighting agent; BAROLIFT® hole sweeping agent;SWEEP-WATE® sweep weighting agent; BDF-508 rheology modifier; andGELTONE® II organophilic clay. In various embodiments, the compositionor a mixture including the same can include one or more additivecomponents such as: X-TEND® II, PAC™-R, PAC™-L, LIQUI-VIS® EP,BRINEDRIL-VIS™, BARAZAN®, N-VIS®, and AQUAGEL® viscosifiers;THERMA-CHEK®, N-DRIL™, N-DRIL™ HT PLUS, IMPERMEX®, FILTERCHEK™,DEXTRID®, CARBONOX®, and BARANEX® filtration control agents;PERFORMATROL®, GEM™, EZ-MUD®, CLAY GRABBER®, CLAYSEAL®, CRYSTAL-DRIL®,and CLAY SYNC™ II shale stabilizers; NXS-LUBE™, EP MUDLUBE®, andDRIL-N-SLIDE™ lubricants; QUIK-THIN®, IRON-THIN™, THERMA-THIN™, andENVIRO-THIN™ thinners; SOURSCAV™ scavenger; BARACOR® corrosioninhibitor; and WALL-NUT®, SWEEP-WATE®, STOPPIT™, PLUG-GIT®, BARACARB®,DUO-SQUEEZE®, BAROFIBRE™, STEELSEAL®, and HYDRO-PLUG® lost circulationmanagement materials. Any suitable proportion of the composition ormixture including the composition can include any optional componentlisted in this paragraph, such as about 0.001 wt % to about 99.999 wt %,about 0.01 wt % to about 99.99 wt %, about 0.1 wt % to about 99.9 wt %,about 20 to about 90 wt %, or about 0.001 wt % or less, or about 0.01 wt%, 0.1, 1, 2, 3, 4, 5, 10, 15, 20, 30, 40, 50, 60, 70, 80, 85, 90, 91,92, 93, 94, 95, 96, 97, 98, 99, 99.9, 99.99 wt %, or about 99.999 wt %or more of the composition or mixture.

A drilling fluid, also known as a drilling mud or simply “mud,” is aspecially designed fluid that is circulated through a wellbore as thewellbore is being drilled to facilitate the drilling operation. Thedrilling fluid can be water-based or oil-based. The drilling fluid cancarry cuttings up from beneath and around the bit, transport them up theannulus, and allow their separation. Also, a drilling fluid can cool andlubricate the drill bit as well as reduce friction between the drillstring and the sides of the hole. The drilling fluid aids in support ofthe drill pipe and drill bit, and provides a hydrostatic head tomaintain the integrity of the wellbore walls and prevent well blowouts.Specific drilling fluid systems can be selected to optimize a drillingoperation in accordance with the characteristics of a particulargeological formation. The drilling fluid can be formulated to preventunwanted influxes of formation fluids from permeable rocks and also toform a thin, low permeability filter cake that temporarily seals pores,other openings, and formations penetrated by the bit. In water-baseddrilling fluids, solid particles are suspended in a water or brinesolution containing other components. Oils or other non-aqueous liquidscan be emulsified in the water or brine or at least partiallysolubilized (for less hydrophobic non-aqueous liquids), but water is thecontinuous phase. A drilling fluid can be present in the composition ora mixture including the same in any suitable amount, such as about 1 wt% or less, about 2 wt %, 3, 4, 5, 10, 15, 20, 30, 40, 50, 60, 70, 80,85, 90, 95, 96, 97, 98, 99, 99.9, 99.99, or about 99.999 wt % or more.

A water-based drilling fluid in embodiments of the present invention canbe any suitable water-based drilling fluid. In various embodiments, thedrilling fluid can include at least one of water (fresh or brine), asalt (e.g., calcium chloride, sodium chloride, potassium chloride,magnesium chloride, calcium bromide, sodium bromide, potassium bromide,calcium nitrate, sodium formate, potassium formate, cesium formate),aqueous base (e.g., sodium hydroxide or potassium hydroxide), alcohol orpolyol, cellulose, starches, alkalinity control agents, density controlagents such as a density modifier (e.g., barium sulfate), surfactants(e.g., betaines, alkali metal alkylene acetates, sultaines, ethercarboxylates), emulsifiers, dispersants, polymeric stabilizers,crosslinking agents, polyacrylamides, polymers or combinations ofpolymers, antioxidants, heat stabilizers, foam control agents, solvents,diluents, plasticizers, filler or inorganic particles (e.g., silica),pigments, dyes, precipitating agents (e.g., silicates or aluminumcomplexes), and rheology modifiers such as thickeners or viscosifiers(e.g., xanthan gum). Any ingredient listed in this paragraph can beeither present or not present in the mixture.

A pill is a relatively small quantity (e.g., less than about 500 bbl, orless than about 200 bbl) of drilling fluid used to accomplish a specifictask that the regular drilling fluid cannot perform. For example, a pillcan be a high-viscosity pill to, for example, help lift cuttings out ofa vertical wellbore. In another example, a pill can be a freshwater pillto, for example, dissolve a salt formation. Another example is apipe-freeing pill to, for example, destroy filter cake and relievedifferential sticking forces. In another example, a pill is a lostcirculation material pill to, for example, plug a thief zone. A pill caninclude any component described herein as a component of a drillingfluid.

A cement fluid can include an aqueous mixture of at least one of cementand cement kiln dust. The composition including the crosslinkedviscosifier polymer can form a useful combination with cement or cementkiln dust. The cement kiln dust can be any suitable cement kiln dust.Cement kiln dust can be formed during the manufacture of cement and canbe partially calcined kiln feed that is removed from the gas stream andcollected in a dust collector during a manufacturing process. Cementkiln dust can be advantageously utilized in a cost-effective mannersince kiln dust is often regarded as a low value waste product of thecement industry. Some embodiments of the cement fluid can include cementkiln dust but no cement, cement kiln dust and cement, or cement but nocement kiln dust. The cement can be any suitable cement. The cement canbe a hydraulic cement. A variety of cements can be utilized inaccordance with embodiments of the present invention; for example, thoseincluding calcium, aluminum, silicon, oxygen, iron, or sulfur, which canset and harden by reaction with water. Suitable cements can includePortland cements, pozzolana cements, gypsum cements, high aluminacontent cements, slag cements, silica cements, and combinations thereof.In some embodiments, the Portland cements that are suitable for use inembodiments of the present invention are classified as Classes A, C, H,and G cements according to the American Petroleum Institute, APISpecification for Materials and Testing for Well Cements, APISpecification 10, Fifth Ed., Jul. 1, 1990. A cement can be generallyincluded in the cementing fluid in an amount sufficient to provide thedesired compressive strength, density, or cost. In some embodiments, thehydraulic cement can be present in the cementing fluid in an amount inthe range of from 0 wt % to about 100 wt %, about 0 wt % to about 95 wt%, about 20 wt % to about 95 wt %, or about 50 wt % to about 90 wt %. Acement kiln dust can be present in an amount of at least about 0.01 wt%, or about 5 wt % to about 80 wt %, or about 10 wt % to about 50 wt %.

Optionally, other additives can be added to a cement or kilndust-containing composition of embodiments of the present invention asdeemed appropriate by one skilled in the art, with the benefit of thisdisclosure. Any optional ingredient listed in this paragraph can beeither present or not present in the composition. For example, thecomposition can include fly ash, metakaolin, shale, zeolite, setretarding additive, surfactant, a gas, accelerators, weight reducingadditives, heavy-weight additives, lost circulation materials,filtration control additives, dispersants, and combinations thereof. Insome examples, additives can include crystalline silica compounds,amorphous silica, salts, fibers, hydratable clays, microspheres,pozzolan lime, thixotropic additives, combinations thereof, and thelike.

In various embodiments, the composition or mixture can include aproppant, a resin-coated proppant, an encapsulated resin, or acombination thereof. A proppant is a material that keeps an inducedhydraulic fracture at least partially open during or after a fracturingtreatment. Proppants can be transported into the subterranean formation(e.g., downhole) to the fracture using fluid, such as fracturing fluidor another fluid. A higher-viscosity fluid can more effectivelytransport proppants to a desired location in a fracture, especiallylarger proppants, by more effectively keeping proppants in a suspendedstate within the fluid. Examples of proppants can include sand, gravel,glass beads, polymer beads, ground products from shells and seeds suchas walnut hulls, and manmade materials such as ceramic proppant,bauxite, tetrafluoroethylene materials (e.g., TEFLON™polytetrafluoroethylene), fruit pit materials, processed wood, compositeparticulates prepared from a binder and fine grade particulates such assilica, alumina, fumed silica, carbon black, graphite, mica, titaniumdioxide, meta-silicate, calcium silicate, kaolin, talc, zirconia, boron,fly ash, hollow glass microspheres, and solid glass, or mixturesthereof. In some embodiments, the proppant can have an average particlesize, wherein particle size is the largest dimension of a particle, ofabout 0.001 mm to about 3 mm, about 0.15 mm to about 2.5 mm, about 0.25mm to about 0.43 mm, about 0.43 mm to about 0.85 mm, about 0.85 mm toabout 1.18 mm, about 1.18 mm to about 1.70 mm, or about 1.70 to about2.36 mm. In some embodiments, the proppant can have a distribution ofparticle sizes clustering around multiple averages, such as one, two,three, or four different average particle sizes. The composition ormixture can include any suitable amount of proppant, such as about 0.01wt % to about 99.99 wt %, about 0.1 wt % to about 80 wt %, about 10 wt %to about 60 wt %, or about 0.01 wt % or less, or about 0.1 wt %, 1, 2,3, 4, 5, 10, 15, 20, 30, 40, 50, 60, 70, 80, 85, 90, 91, 92, 93, 94, 95,96, 97, 98, 99, about 99.9 wt %, or about 99.99 wt % or more.

Drilling Assembly.

In various embodiments, the composition including the crosslinkedviscosifier polymer disclosed herein can directly or indirectly affectone or more components or pieces of equipment associated with thepreparation, delivery, recapture, recycling, reuse, and/or disposal ofthe disclosed composition including the crosslinked viscosifier polymer.For example, and with reference to FIG. 1, the disclosed compositionincluding the crosslinked viscosifier polymer can directly or indirectlyaffect one or more components or pieces of equipment associated with anexemplary wellbore drilling assembly 100, according to one or moreembodiments. It should be noted that while FIG. 1 generally depicts aland-based drilling assembly, those skilled in the art will readilyrecognize that the principles described herein are equally applicable tosubsea drilling operations that employ floating or sea-based platformsand rigs, without departing from the scope of the disclosure.

As illustrated, the drilling assembly 100 can include a drillingplatform 102 that supports a derrick 104 having a traveling block 106for raising and lowering a drill string 108. The drill string 108 caninclude drill pipe and coiled tubing, as generally known to thoseskilled in the art. A kelly 110 supports the drill string 108 as it islowered through a rotary table 112. A drill bit 114 is attached to thedistal end of the drill string 108 and is driven either by a downholemotor and/or via rotation of the drill string 108 from the well surface.As the bit 114 rotates, it creates a wellbore 116 that penetratesvarious subterranean formations 118.

A pump 120 (e.g., a mud pump) circulates drilling fluid 122 through afeed pipe 124 and to the kelly 110, which conveys the drilling fluid 122downhole through the interior of the drill string 108 and through one ormore orifices in the drill bit 114. The drilling fluid 122 is thencirculated back to the surface via an annulus 126 defined between thedrill string 108 and the walls of the wellbore 116. At the surface, therecirculated or spent drilling fluid 122 exits the annulus 126 and canbe conveyed to one or more fluid processing unit(s) 128 via aninterconnecting flow line 130. After passing through the fluidprocessing unit(s) 128, a “cleaned” drilling fluid 122 is deposited intoa nearby retention pit 132 (e.g., a mud pit). While illustrated as beingarranged at the outlet of the wellbore 116 via the annulus 126, thoseskilled in the art will readily appreciate that the fluid processingunit(s) 128 can be arranged at any other location in the drillingassembly 100 to facilitate its proper function, without departing fromthe scope of the disclosure.

The composition including the crosslinked viscosifier polymer can beadded to the drilling fluid 122 via a mixing hopper 134 communicablycoupled to or otherwise in fluid communication with the retention pit132. The mixing hopper 134 can include mixers and related mixingequipment known to those skilled in the art. In other embodiments,however, the composition including the crosslinked viscosifier polymercan be added to the drilling fluid 122 at any other location in thedrilling assembly 100. In at least one embodiment, for example, therecould be more than one retention pit 132, such as multiple retentionpits 132 in series. Moreover, the retention pit 132 can berepresentative of one or more fluid storage facilities and/or unitswhere the composition including the crosslinked viscosifier polymer canbe stored, reconditioned, and/or regulated until added to the drillingfluid 122.

As mentioned above, the composition including the crosslinkedviscosifier polymer can directly or indirectly affect the components andequipment of the drilling assembly 100. For example, the compositionincluding the crosslinked viscosifier polymer can directly or indirectlyaffect the fluid processing unit(s) 128, which can include one or moreof a shaker (e.g., shale shaker), a centrifuge, a hydrocyclone, aseparator (including magnetic and electrical separators), a desilter, adesander, a separator, a filter (e.g., diatomaceous earth filters), aheat exchanger, or any fluid reclamation equipment. The fluid processingunit(s) 128 can further include one or more sensors, gauges, pumps,compressors, and the like used to store, monitor, regulate, and/orrecondition the composition including the crosslinked viscosifierpolymer.

The composition including the crosslinked viscosifier polymer candirectly or indirectly affect the pump 120, which representativelyincludes any conduits, pipelines, trucks, tubulars, and/or pipes used tofluidically convey the composition including the crosslinked viscosifierpolymer to the subterranean formation, any pumps, compressors, or motors(e.g., topside or downhole) used to drive the composition into motion,any valves or related joints used to regulate the pressure or flow rateof the composition, and any sensors (e.g., pressure, temperature, flowrate, and the like), gauges, and/or combinations thereof, and the like.The composition including the crosslinked viscosifier polymer can alsodirectly or indirectly affect the mixing hopper 134 and the retentionpit 132 and their assorted variations.

The composition including the crosslinked viscosifier polymer can alsodirectly or indirectly affect the various downhole or subterraneanequipment and tools that can come into contact with the compositionincluding the crosslinked viscosifier polymer such as the drill string108, any floats, drill collars, mud motors, downhole motors, and/orpumps associated with the drill string 108, and any measurement whiledrilling (MWD)/logging while drilling (LWD) tools and related telemetryequipment, sensors, or distributed sensors associated with the drillstring 108. The composition including the crosslinked viscosifierpolymer can also directly or indirectly affect any downhole heatexchangers, valves and corresponding actuation devices, tool seals,packers and other wellbore isolation devices or components, and the likeassociated with the wellbore 116. The composition including thecrosslinked viscosifier polymer can also directly or indirectly affectthe drill bit 114, which can include roller cone bits, polycrystallinediamond compact (PDC) bits, natural diamond bits, hole openers, reamers,coring bits, and the like.

While not specifically illustrated herein, the composition including thecrosslinked viscosifier polymer can also directly or indirectly affectany transport or delivery equipment used to convey the compositionincluding the crosslinked viscosifier polymer to the drilling assembly100 such as, for example, any transport vessels, conduits, pipelines,trucks, tubulars, and/or pipes used to fluidically move the compositionincluding the crosslinked viscosifier polymer from one location toanother, any pumps, compressors, or motors used to drive the compositioninto motion, any valves or related joints used to regulate the pressureor flow rate of the composition, and any sensors (e.g., pressure andtemperature), gauges, and/or combinations thereof, and the like.

System or Apparatus.

In various embodiments, the present invention provides a system. Thesystem can be any suitable system that can use or that can be generatedby use of an embodiment of the composition described herein in asubterranean formation, or that can perform or be generated byperformance of a method for using the composition described herein. Thesystem can include a composition including the crosslinked viscosifierpolymer, e.g., a crosslinked viscosifier polymer including an ethylenerepeating unit including an —S(O)₂OR¹ group wherein at each occurrenceR¹ is independently chosen from —H, substituted or unsubstituted(C₁-C₂₀)hydrocarbyl, and a counterion. The system can also include asubterranean formation including the composition therein. In someembodiments, the composition in the system can also include a downholefluid, or the system can include a mixture of the composition anddownhole fluid. In some embodiments, the system can include a tubular,and a pump configured to pump the composition into the subterraneanformation through the tubular.

Various embodiments provide systems and apparatus configured fordelivering the composition described herein to a subterranean locationand for using the composition therein, such as for a drilling operation,or a fracturing operation (e.g., pre-pad, pad, slurry, or finishingstages). In various embodiments, the system or apparatus can include apump fluidly coupled to a tubular (e.g., any suitable type of oilfieldpipe, such as pipeline, drill pipe, production tubing, and the like),with the tubular containing a composition including the crosslinkedviscosifier polymer described herein.

In some embodiments, the system can include a drill string disposed in awellbore, with the drill string including a drill bit at a downhole endof the drill string. The system can also include an annulus between thedrill string and the wellbore. The system can also include a pumpconfigured to circulate the composition through the drill string,through the drill bit, and back above-surface through the annulus. Insome embodiments, the system can include a fluid processing unitconfigured to process the composition exiting the annulus to generate acleaned drilling fluid for recirculation through the wellbore.

In various embodiments, the present invention provides an apparatus. Theapparatus can be any suitable apparatus that can use or that can begenerated by use of the composition including the crosslinkedviscosifier polymer described herein in a subterranean formation, orthat can perform or be generated by performance of a method for usingthe composition described herein.

The pump can be a high pressure pump in some embodiments. As usedherein, the term “high pressure pump” will refer to a pump that iscapable of delivering a fluid to a subterranean formation (e.g.,downhole) at a pressure of about 1000 psi or greater. A high pressurepump can be used when it is desired to introduce the composition to asubterranean formation at or above a fracture gradient of thesubterranean formation, but it can also be used in cases wherefracturing is not desired. In some embodiments, the high pressure pumpcan be capable of fluidly conveying particulate matter, such as proppantparticulates, into the subterranean formation. Suitable high pressurepumps will be known to one having ordinary skill in the art and caninclude floating piston pumps and positive displacement pumps.

In other embodiments, the pump can be a low pressure pump. As usedherein, the term “low pressure pump” will refer to a pump that operatesat a pressure of about 1000 psi or less. In some embodiments, a lowpressure pump can be fluidly coupled to a high pressure pump that isfluidly coupled to the tubular. That is, in such embodiments, the lowpressure pump can be configured to convey the composition to the highpressure pump. In such embodiments, the low pressure pump can “step up”the pressure of the composition before it reaches the high pressurepump.

In some embodiments, the systems or apparatuses described herein canfurther include a mixing tank that is upstream of the pump and in whichthe composition is formulated. In various embodiments, the pump (e.g., alow pressure pump, a high pressure pump, or a combination thereof) canconvey the composition from the mixing tank or other source of thecomposition to the tubular. In other embodiments, however, thecomposition can be formulated offsite and transported to a worksite, inwhich case the composition can be introduced to the tubular via the pumpdirectly from its shipping container (e.g., a truck, a railcar, a barge,or the like) or from a transport pipeline. In either case, thecomposition can be drawn into the pump, elevated to an appropriatepressure, and then introduced into the tubular for delivery to thesubterranean formation.

FIG. 2 shows an illustrative schematic of systems and apparatuses thatcan deliver embodiments of the compositions of the present invention toa subterranean location, according to one or more embodiments. It shouldbe noted that while FIG. 2 generally depicts a land-based system orapparatus, it is to be recognized that like systems and apparatuses canbe operated in subsea locations as well. Embodiments of the presentinvention can have a different scale than that depicted in FIG. 2. Asdepicted in FIG. 2, system or apparatus 1 can include mixing tank 10, inwhich an embodiment of the composition can be formulated. Thecomposition can be conveyed via line 12 to wellhead 14, where thecomposition enters tubular 16, with tubular 16 extending from wellhead14 into subterranean formation 18. Upon being ejected from tubular 16,the composition can subsequently penetrate into subterranean formation18. Pump 20 can be configured to raise the pressure of the compositionto a desired degree before its introduction into tubular 16. It is to berecognized that system or apparatus 1 is merely exemplary in nature andvarious additional components can be present that have not necessarilybeen depicted in FIG. 2 in the interest of clarity. In some examples,additional components that can be present include supply hoppers,valves, condensers, adapters, joints, gauges, sensors, compressors,pressure controllers, pressure sensors, flow rate controllers, flow ratesensors, temperature sensors, and the like.

Although not depicted in FIG. 2, at least part of the composition can,in some embodiments, flow back to wellhead 14 and exit subterraneanformation 18. The composition that flows back can be substantiallydiminished in the concentration of the crosslinked viscosifier polymertherein. In some embodiments, the composition that has flowed back towellhead 14 can subsequently be recovered, and in some examplesreformulated, and recirculated to subterranean formation 18.

It is also to be recognized that the disclosed composition can alsodirectly or indirectly affect the various downhole or subterraneanequipment and tools that can come into contact with the compositionduring operation. Such equipment and tools can include wellbore casing,wellbore liner, completion string, insert strings, drill string, coiledtubing, slickline, wireline, drill pipe, drill collars, mud motors,downhole motors and/or pumps, surface-mounted motors and/or pumps,centralizers, turbolizers, scratchers, floats (e.g., shoes, collars,valves, and the like), logging tools and related telemetry equipment,actuators (e.g., electromechanical devices, hydromechanical devices, andthe like), sliding sleeves, production sleeves, plugs, screens, filters,flow control devices (e.g., inflow control devices, autonomous inflowcontrol devices, outflow control devices, and the like), couplings(e.g., electro-hydraulic wet connect, dry connect, inductive coupler,and the like), control lines (e.g., electrical, fiber optic, hydraulic,and the like), surveillance lines, drill bits and reamers, sensors ordistributed sensors, downhole heat exchangers, valves and correspondingactuation devices, tool seals, packers, cement plugs, bridge plugs, andother wellbore isolation devices or components, and the like. Any ofthese components can be included in the systems and apparatusesgenerally described above and depicted in FIG. 2.

Composition for Treatment of a Subterranean Formation.

Various embodiments provide a composition for treatment of asubterranean formation. The composition can be any suitable compositionthat can be used to perform an embodiment of the method for treatment ofa subterranean formation described herein. For example, the compositioncan include a crosslinked viscosifier polymer including an ethylenerepeating unit including an —S(O)₂OR¹ group wherein at each occurrenceR¹ is independently chosen from —H, substituted or unsubstituted(C₁-C₂₀)hydrocarbyl, and a counterion. The composition can be acomposition for drilling into a reservoir in a subterranean formation(e.g., a drill-in fluid). The composition can be an aqueous drillingmud.

The composition can further include any suitable component, such ascomponents typically used in drilling fluid compositions. Thecomposition can be substantially clay-free, e.g., the composition canhave less than about 5 wt %, 4, 3, 2, 1.5, 1, 0.5, 0.4, 0.3, 0.2, 0.1,0.05, or less than about 0.01 wt % clay. The composition can include asuitable downhole fluid. In some embodiments, the composition can be acomposition for fracturing a subterranean formation, and the compositioncan further include suitable components typically used in fracturingfluid compositions.

Method for Preparing a Composition for Treatment of a SubterraneanFormation.

In various embodiments, the present invention provides a method forpreparing a composition for treatment of a subterranean formation. Themethod can be any suitable method that produces an embodiment of thecomposition including the crosslinked viscosifier polymer describedherein. For example, the method can include forming a compositionincluding a crosslinked viscosifier polymer including an ethylenerepeating unit including an —S(O)₂OR¹ group wherein at each occurrenceR¹ is independently chosen from —H, substituted or unsubstituted(C₁-C₂₀)hydrocarbyl, and a counterion.

EXAMPLES

Various embodiments of the present invention can be better understood byreference to the following Examples which are offered by way ofillustration. The present invention is not limited to the Examples givenherein. The abbreviation “bbl” is barrel (42 gallons, 159 L), “PV” isplastic viscosity, and “YP” is yield point.

Rheology data was obtained at 120° F. with a Fann 35, and fluid loss wasmeasured on 20 μm ceramic discs (having a filtering area of 22.58 cm²)at 350° F. with a 500 psi pressure differential over 30 minutes. Thevolume collected was multiplied by two to give total fluid loss inaccordance with ANSI/API Recommended Practice 13B-1.

Example 1 Preparation of Samples A-E

The crosslinked viscosifier polymers were synthesized from2-acrylamido-2-methylpropanesulfonic acid (AMPS) by precipitationpolymerization in tert-butanol. The crosslinked viscosifier polymersused in samples A, B, and C were synthesized usingN,N′-divinylethyleneurea (DVEU) as a crosslinker at concentrations of 2mol %, 3 mol % or 4 mol %, respectively, wherein the mol % crosslinkeris with respect to the moles of AMPS used. The crosslinked viscosifierpolymer used in Sample D was synthesized using 50:50 mole ratio of AMPSto N-vinylpyrrolidone (VP) and using 2 mol % DVEU as crosslinker,wherein the mol % crosslinker is with respect to the moles of AMPS andVP used. The crosslinked viscosifier polymer used in Sample E wassynthesized using an 85:15 mole ratio of AMPS to VP and using 6 mol % ofpentaerythritol allyl ether (PAE, having an average of about 3.2 allylgroups per molecule) and 1 mol % of N,N′-methylenebisacrylamide (MBAM).Samples A-E were prepared by using the respective crosslinkedviscosifier polymer in 9.8 lb/gal NaCl/KCl brine and included thecomponents as shown in Table 1.

TABLE 1 Brine-based drill-in mud formulation. Formulation Water, bbl0.877 NaCl, lb 56.5 KCl, lb 19.2 Polypropylene glycol, lb 0.2Crosslinked viscosifier polymer, lb 10 Sodium bicarbonate, lb 4 Calciumcarbonate, 5 micron particle size, lb 32 Calcium carbonate, 25 micronparticle size, lb 8

Example 2 Properties of Samples A-C

The mud Samples A-C were first hot-rolled at 150° F. for 16 hr, thenstatic aged at 400° F. for 3 days. Table 2 shows the drill-in mudproperties with AMPS homopolymers crosslinked with different amounts ofN,N′-divinylethyleneurea (DVEU). It can be seen that the mud becomesmore thermally stable with the increase in DVEU amount. After staticaging at 400° F. for 3 days, the mud still provides reasonable rheologyand good fluid loss control.

TABLE 2 Fluid properties with AMPS polymer with different amount of DVEUcrosslinker. Before hot rolling (BHR), after hot rolling (AHR), afterstatic aging (ASA). SAMPLE A B C DVEU, mol % 2.0 3.0 4.0 PolymerLoading, lb/bbl 10.0 10.0 10.0 Rheology at 120° F. before and afterhot-rolling and after static aging RPM BHR AHR ASA BHR AHR ASA BHR AHRASA 600 rpm, lb/100 ft² 132 116 56 88 84 48 86 89 54 300 rpm, lb/100 ft²94 81 37 61 57 32 59 60 35 200 rpm, lb/100 ft² 77 66 29 49 46 23 48 4927 100 rpm, lb/100 ft² 55 47 19 35 31 14 34 34 17  6 rpm, lb/100 ft² 1814 5 11 10 3 11 10 4  3 rpm, lb/100 ft² 15 11 4 9 8 2 9 8 3  10 s gel,lb/100 ft² 14 11 5 9 8 3 10 8 3  10 m gel, lb/100 ft² 15 11 6 9 9 3 10 93 PV, cP 38 35 19 27 27 16 25 29 19 YP, lb/100 ft² 56 46 18 34 30 16 2931 16 HTHP fluid loss at 350° F., 20 micron ceramic disc, 30 minutesFluid loss, mL (30 min) 28 28 27

Example 3 Properties of Samples D-E

The mud Samples D-E were first hot-rolled at 150° F. for 16 hr, thenstatic aged at 400° F. for 3 days. Table 3 shows the drill-in mudproperties with the AMPS-VP copolymers crosslinked with differentcrosslinkers. For both polymers, the mud remains stable and providesgood filtration control even after static aging at 400° F. for 3 days.It should be noted that the fluid loss can be further decreased byoptimization of mud formulation or testing on ceramic discs with smallerpore sizes.

TABLE 3 Fluid properties with AMPS-VP polymer with differentcrosslinkers. Sample D E Polymer AMPS/VP (50/50) AMPS/VP (85/15)Crosslinker     DVEU (2 mol %) PAE (6 mol %) + MBAM (1 mol %) PolymerLoading, lb/bbl 10.0 10.0 Rheology at 120° F. before and afterhot-rolling and after static aging RPM BHR AHR ASA BHR AHR ASA 600 rpm,lb/100 ft² 91 84 76 85 81 94 300 rpm, lb/100 ft² 63 58 50 59 55 62 200rpm, lb/100 ft² 51 46 40 48 45 49 100 rpm, lb/100 ft² 36 32 27 34 32 34 6 rpm, lb/100 ft² 12 10 8 12 11 10  3 rpm, lb/100 ft² 10 8 7 11 10 8 10 s gel, lb/100 ft² 9 9 7 11 9 8  10 m gel, lb/100 ft² 9 9 7 11 10 8PV, cP 28 26 26 26 26 32 YP, lb/100 ft² 35 32 24 33 29 30 HTHP fluidloss at 350° F., 20 micron ceramic disc, 30 minutes Fluid loss, mL (30min) 30   33

The terms and expressions that have been employed are used as terms ofdescription and not of limitation, and there is no intention in the useof such terms and expressions of excluding any equivalents of thefeatures shown and described or portions thereof, but it is recognizedthat various modifications are possible within the scope of theembodiments of the present invention. Thus, it should be understood thatalthough the present invention has been specifically disclosed byspecific embodiments and optional features, modification and variationof the concepts herein disclosed may be resorted to by those of ordinaryskill in the art, and that such modifications and variations areconsidered to be within the scope of embodiments of the presentinvention.

Additional Embodiments

The following exemplary embodiments are provided, the numbering of whichis not to be construed as designating levels of importance:

Embodiment 1 provides a method of treating a subterranean formation, themethod comprising:

placing in a subterranean formation a composition comprising acrosslinked viscosifier polymer comprising an ethylene repeating unitcomprising an —S(O)₂OR¹ group wherein at each occurrence R¹ isindependently chosen from —H, substituted or unsubstituted(C₁-C₂₀)hydrocarbyl, and a counterion.

Embodiment 2 provides the method of Embodiment 1, wherein thecomposition is a drill-in fluid, wherein the method comprises drillinginto a petroleum reservoir in the subterranean formation using thecomposition.

Embodiment 3 provides the method of any one of Embodiments 1-2, whereinthe composition has less than 5 wt % clay.

Embodiment 4 provides the method of any one of Embodiments 1-3, whereinthe composition has less than 1 wt % clay.

Embodiment 5 provides the method of any one of Embodiments 1-4, whereinthe method further comprises obtaining or providing the composition,wherein the obtaining or providing of the composition occursabove-surface.

Embodiment 6 provides the method of any one of Embodiments 1-5, whereinthe method further comprises obtaining or providing the composition,wherein the obtaining or providing of the composition occurs in thesubterranean formation.

Embodiment 7 provides the method of any one of Embodiments 1-6, whereinthe composition comprises at least one of an aqueous liquid and awater-miscible liquid.

Embodiment 8 provides the method of Embodiment 7, wherein the aqueousliquid comprises at least one of water, brine, produced water, flowbackwater, brackish water, and sea water.

Embodiment 9 provides the method of any one of Embodiments 7-8, whereinthe aqueous liquid comprises salt water having a total dissolved solidslevel of about 1,000 mg/L to about 250,000 mg/L.

Embodiment 10 provides the method of any one of Embodiments 1-9, whereinat 49° C. at standard pressure at 3 rpm to 6 rpm the composition has ashear stress of about 1 lb/100 ft² to about 40 lb/100 ft².

Embodiment 11 provides the method of any one of Embodiments 1-10,wherein at 49° C. at standard pressure at 3 rpm to 6 rpm the compositionhas a shear stress of about 2 lb/100 ft² to about 18 lb/100 ft².

Embodiment 12 provides the method of any one of Embodiments 1-11,wherein at 49° C. at standard pressure at 200 rpm to 600 rpm thecomposition has a shear stress of about 15 lb/100 ft² to about 150lb/100 ft².

Embodiment 13 provides the method of any one of Embodiments 1-12,wherein at 49° C. at standard pressure at 200 rpm to 600 rpm thecomposition has a shear stress of about 20 lb/100 ft² to about 135lb/100 ft².

Embodiment 14 provides the method of any one of Embodiments 1-13,wherein at 49° C. at standard pressure the composition has a plasticviscosity of about 10 cP to about 60 cP.

Embodiment 15 provides the method of any one of Embodiments 1-14,wherein at 49° C. at standard pressure the composition has a plasticviscosity of about 15 cP to about 40 cP.

Embodiment 16 provides the method of any one of Embodiments 1-15,wherein at 49° C. at standard pressure the composition has a yield pointof about 10 lb/100 ft² to about 80 lb/100 ft².

Embodiment 17 provides the method of any one of Embodiments 1-16,wherein at 49° C. at standard pressure the composition has a yield pointof about 15 lb/100 ft² to about 60 lb/100 ft².

Embodiment 18 provides the method of any one of Embodiments 1-17,wherein at 177° C. using a 20 micron ceramic disc for 30 minutes with500 psi pressure differential and multiplying the volume of fluid thatgoes through the disc by two, the composition has a fluid loss of lessthan about 40 mL.

Embodiment 19 provides the method of any one of Embodiments 1-18,wherein at 177° C. using a 20 micron ceramic disc for 30 minutes with500 psi pressure differential and multiplying the volume of fluid thatgoes through the disc by two, the composition has a fluid loss of about20 mL to about 35 mL.

Embodiment 20 provides the method of any one of Embodiments 1-19,wherein about 0.01 wt % to about 100 wt % of the composition is thecrosslinked viscosifier polymer.

Embodiment 21 provides the method of any one of Embodiments 1-20,wherein about 0.1 wt % to about 10 wt % of the composition is thecrosslinked viscosifier polymer.

Embodiment 22 provides the method of any one of Embodiments 1-21,wherein the crosslinked viscosifier polymer has about A^(mol) mol % ofthe repeating unit comprising the —S(O)₂OR¹, wherein A^(mol) is about 30mol % to about 99 mol %.

Embodiment 23 provides the method of Embodiment 22, wherein A^(mol) isabout 80 mol % to about 99 mol %.

Embodiment 24 provides the method of any one of Embodiments 1-23,wherein the crosslinked viscosifier polymer comprises repeating unitshaving the structure:

wherein

-   -   the repeating units are in a block, alternate, or random        configuration, and each repeating unit is independently in the        orientation shown or in the opposite orientation,    -   at each occurrence R^(A), R^(B), and R^(C) are independently        selected from the group consisting of —H and a substituted or        unsubstituted (C₁-C₅)hydrocarbyl, and    -   at each occurrence L¹ is independently selected from the group        consisting of a bond and a substituted or unsubstituted        (C₁-C₄₀)hydrocarbyl interrupted or terminated with 0, 1, 2, or 3        of at least one of —S—, —O—, and substituted or unsubstituted        —NH—.

Embodiment 25 provides the method of Embodiment 24, wherein at eachoccurrence R^(A), R^(B), and R^(C) are independently selected from thegroup consisting of —H and a (C₁-C₅)alkyl.

Embodiment 26 provides the method of any one of Embodiments 24-25,wherein at each occurrence R^(A), R^(B), and R^(C) are independentlyselected from the group consisting of —H and a (C₁-C₃)alkyl.

Embodiment 27 provides the method of any one of Embodiments 24-26,wherein at each occurrence R^(A), R^(B), and R^(C) are each —H.

Embodiment 28 provides the method of any one of Embodiments 1-27,wherein at each occurrence R¹ is independently selected from the groupconsisting of —H, Na⁺, K⁺, Li⁺, NH₄ ⁺, Zn⁺, Ca²⁺, Zn²⁺, Al³⁺, Mg²⁺, andNR^(E) ₄, wherein at each occurrence R^(E) is independently chosen from—H and substituted or unsubstituted (C₁-C₃₀)hydrocarbyl interrupted by0, 1, 2, or 3 groups independently chosen from —O—, —S—, and substitutedor unsubstituted —NH—, or wherein two or three R^(E) groups togetherform a substituted or unsubstituted (C₁-C₃₀)hydrocarbylene or(C₁-C₃₀)hydrocarbtriyl interrupted by 0, 1, 2, or 3 groups independentlychosen from —O—, —S—, and substituted or unsubstituted —NH—.

Embodiment 29 provides the method of any one of Embodiments 1-28,wherein at each occurrence R¹ is (C₁-C₅)alkyl.

Embodiment 30 provides the method of any one of Embodiments 1-29,wherein at each occurrence R¹ is —H.

Embodiment 31 provides the method of any one of Embodiments 24-30,wherein at each occurrence L¹ is independently selected from the groupconsisting of a bond and -(substituted or unsubstituted(C₁-C₂₀)hydrocarbyl)-NR³-(substituted or unsubstituted(C₁-C₂₀)hydrocarbyl)-.

Embodiment 32 provides the method of any one of Embodiments 24-31,wherein at each occurrence L¹ is independently —C(O)—NH—(substituted orunsubstituted (C₁-C₂₀)hydrocarbyl)-.

Embodiment 33 provides the method of any one of Embodiments 24-32,wherein at each occurrence L¹ is independently—C(O)—NH—((C₁-C₅)hydrocarbyl)-.

Embodiment 34 provides the method of any one of Embodiments 24-33,wherein L¹ is —C(O)—NH—CH(CH₃)₂—CH₂—.

Embodiment 35 provides the method of any one of Embodiments 24-34,wherein a is about 2 to about 10,000,000.

Embodiment 36 provides the method of any one of Embodiments 24-35,wherein a is about 10 to about 500,000.

Embodiment 37 provides the method of any one of Embodiments 1-36,wherein the ethylene repeating unit comprising the —S(O)₂OR¹ group is a2-acrylamido-2-methylpropanesulfonic acid repeating unit or a salt or(C₁-C₅)alkyl ester thereof.

Embodiment 38 provides the method of any one of Embodiments 1-37,wherein in addition to the ethylene repeating unit comprising the—S(O)₂OR¹ group, the crosslinked viscosifier polymer also comprises acomonomer b that is an ethylene repeating unit comprising at least oneof a —C(O)—NH₂ group, a —C(O)—NHR^(D) group, a —C(O)—NR^(D) ₂ group, a—C(O)—OH group or a salt thereof, a —C(O)—OR^(D) group, a—NR^(D)—C(O)—R^(D) group, and a —(C₁₋₂₀)heterocyclyl, wherein the—(C₁₋₂₀)heterocyclyl is a nitrogen-containing heterocycle substituentbound to the ethylene repeating unit via a nitrogen atom in theheterocyclic ring, and wherein R^(D) at each occurrence is independentlyselected from —H and substituted or unsubstituted (C₁-C₅₀)hydrocarbylinterrupted by 0, 1, 2, or 3 groups independently selected from —O—,—S—, and substituted or unsubstituted —NH—.

Embodiment 39 provides the method of Embodiment 38, wherein thecomonomer b is ethylene repeating unit comprising at least one of a—C(O)—NH₂ group, a —C(O)—OH group or a salt or (C₁-C₅) alkyl esterthereof, a —C(O)—OR^(D) group, and —N-pyrrolidinyl.

Embodiment 40 provides the method of any one of Embodiments 38-39,wherein the comonomer b is a repeating unit chosen from acrylamide,methacrylamide, acrylic acid, methacrylic acid, N-vinyl lactam, anN-vinylamide, N-vinylpyrrolidone, an acrylate ester, a methacrylateester, and an N-substituted acrylamide.

Embodiment 41 provides the method of any one of Embodiments 38-40,wherein the crosslinked viscosifier polymer has about B^(mol) mol % ofthe comonomer b, wherein B^(mol) is about 0 mol % to about 70 mol %.

Embodiment 42 provides the method of Embodiment 41, wherein B^(mol) isabout 1 mol % to about 20 mol %.

Embodiment 43 provides the method of any one of Embodiments 1-42,wherein the crosslinked viscosifier polymer comprises repeating unitshaving the structure:

wherein

-   -   the repeating units are in a block, alternate, or random        configuration, and each repeating unit is independently in the        orientation shown or in the opposite orientation,    -   at each occurrence R^(A), R^(B), and R^(C) are independently        selected from the group consisting of —H and a substituted or        unsubstituted (C₁-C₅)hydrocarbyl,    -   at each occurrence L¹ and L² are each independently selected        from the group consisting of a bond and a substituted or        unsubstituted (C₁-C₄₀)hydrocarbyl interrupted or terminated with        0, 1, 2, or 3 of at least one of —S—, —O—, and substituted or        unsubstituted —NH—, and    -   at each occurrence Z is independently chosen from a —OR^(D)        group, a —O—C(O)—R^(D) group, —C(O)—NH₂ group, a —C(O)—NHR^(D)        group, a —C(O)—NR^(D) ₂ group, a —C(O)—OH group or a salt        thereof, a —C(O)—OR^(D) group, a —NR^(D)—C(O)—R^(D) group, and a        —(C₁₋₂₀)heterocyclyl, wherein the —(C₁₋₂₀)heterocyclyl is a        nitrogen-containing heterocycle substituent bound to the        ethylene repeating unit via a nitrogen atom in the heterocyclic        ring, and wherein R^(D) at each occurrence is independently        selected from —H and substituted or unsubstituted        (C₁-C₅₀)hydrocarbyl interrupted by 0, 1, 2, or 3 groups        independently selected from —O—, —S—, and substituted or        unsubstituted —NH—.

Embodiment 44 provides the method of Embodiment 43, wherein R^(D) ateach occurrence is independently selected from —H and substituted orunsubstituted (C₁-C₁₀)hydrocarbyl.

Embodiment 45 provides the method of any one of Embodiments 43-44,wherein R^(D) at each occurrence is independently selected from —H andsubstituted or unsubstituted (C₁-C₁₀)alkyl.

Embodiment 46 provides the method of any one of Embodiments 43-45,wherein at each occurrence L² is independently selected from a bond anda (C₁-C₂₀)hydrocarbyl.

Embodiment 47 provides the method of any one of Embodiments 43-46,wherein at each occurrence L² is independently selected from a bond anda (C₁-C₅)alkyl.

Embodiment 48 provides the method of any one of Embodiments 43-47,wherein at each occurrence L² is a bond.

Embodiment 49 provides the method of any one of Embodiments 43-48,wherein b is about 0 to about 1,000,000.

Embodiment 50 provides the method of any one of Embodiments 43-49,wherein b is about 5 to about 100,000.

Embodiment 51 provides the method of any one of Embodiments 1-50,wherein in addition to the ethylene repeating unit comprising the—S(O)₂OR¹ group, the crosslinked viscosifier polymer also comprises acrosslinker that is an ethylene repeating unit comprising a crosslinkinggroup L^(CL), wherein at each occurrence L^(CL) is independently a-(substituted or unsubstituted (C₁-C₄₀)hydrocarbylene)-M, wherein the(C₁-C₄₀)hydrocarbylene is substituted or unsubstituted and isinterrupted by 0, 1, 2, or 3 groups independently selected from —O—,—S—, substituted or unsubstituted —NH—, and—((C₂-C₅)alkoxy)_(n1)—wherein at each occurrence M is independently anethylene repeating unit of the same crosslinked viscosifier polymermolecule or an ethylene repeating unit of another molecule of thecrosslinked viscosifier polymer, wherein n1 is about 2 to about 10,000.

Embodiment 52 provides the method of Embodiment 51, wherein thecrosslinked viscosifier polymer has about C^(mol) mol % of thecrosslinker, wherein C^(mol) is about 0.01 mol % to about 30 mol %.

Embodiment 53 provides the method of Embodiment 52, wherein C^(mol) isabout 0.1 mol % to about 10 mol %.

Embodiment 54 provides the method of any one of Embodiments 1-53,wherein the crosslinked viscosifier is crosslinked via at least onecrosslinker selected from methylenebisacrylamide, ethylenebisacrylamide,ethylene glycol dimethacrylate, a polyethylene glycol dimethacrylate,1,1,1-trimethylolpropane trimethacrylate, divinyl ether, diallyl ether,a vinyl or allyl ether of a polyglycol or a polyol, a divinylbenzene,N,N′-divinylethyleneurea, divinyltetrahydropyrimidin-2(1H)-one, a diene,an allyl amine, N-vinyl-3(E)-ethylidene pyrrolidone, and ethylidenebis(N-vinylpyrrolidone).

Embodiment 55 provides the method of any one of Embodiments 1-54,wherein the crosslinked viscosifier polymer comprises repeating unitshaving the structure:

wherein

-   -   the repeating units are in a block, alternate, or random        configuration, and each repeating unit is independently in the        orientation shown or in the opposite orientation,    -   at each occurrence R^(A), R^(B), and R^(C) are independently        selected from the group consisting of —H and a substituted or        unsubstituted (C₁-C₅)hydrocarbyl,    -   at each occurrence L¹ is independently selected from the group        consisting of a bond and a substituted or unsubstituted        (C₁-C₄₀)hydrocarbyl interrupted or terminated with 0, 1, 2, or 3        of at least one of —S—, —O—, and substituted or unsubstituted        —NH—, and    -   at each occurrence L^(CL) is independently chosen from a        —((C₁-C₁₀)heterocyclylene)- and a -(substituted or unsubstituted        (C₁-C₄₀)hydrocarbylene)-M, wherein the (C₁-C₄₀)hydrocarbylene is        substituted or unsubstituted and is interrupted by 0, 1, 2, or 3        groups independently selected from —O—, —S—, substituted or        unsubstituted —NH—, and —((C₂-C₅)alkoxy)_(n1)-, wherein at each        occurrence M is independently an ethylene repeating unit of the        same crosslinked viscosifier polymer molecule or an ethylene        repeating unit of another molecule of the crosslinked        viscosifier polymer, wherein n1 is about 2 to about 10,000.

Embodiment 56 provides the method of Embodiment 55, wherein at eachoccurrence L^(CL) is independently chosen from—C(O)—NH—R^(CL1)—NH—C(O)-M, —C(O)—(O—R^(CL1))_(n2)—O—C(O)-M,—C(O)—O—CR^(CL2)(O—C(O)-M)₂, —R^(CL1)—O—R^(CL1)—C(—R^(CL1)—R^(CL3))₃,—O-M, —R^(CL1)—O—R^(CL1)-M, —R^(CL1)—O-M, —O—R^(CL1)-M, N,N-boundtetrahydropyrimidin-2(1H)-one, N,3-bound pyrrolidone, 1,3-bound2-imidazolidone, and N,N-bound pyrrolidone-R^(CL1)-pyrrolidone whereinthe pyrrolidones are bound to R^(CL1) via the 3-positions, whereinR^(CL1) is a substituted or unsubstituted (C₁-C₄₀)hydrocarbylene,R^(CL2) is chosen from H and a substituted or unsubstituted(C₁-C₄₀)hydrocarbylene, R^(CL3) is R^(CL2) or —R^(CL1)-M, and R^(CL1)and R^(CL2) are interrupted by 0, 1, 2, or 3 groups independently chosenfrom —O—, —S—, and substituted or unsubstituted —NH, and n2 is about 0to about 10,000.

Embodiment 57 provides the method of Embodiment 56, wherein at eachoccurrence R^(CL1) is independently (C₁-C₅)alkylene.

Embodiment 58 provides the method of any one of Embodiments 56-57,wherein at each occurrence R^(CL2) is independently (C₁-C₅)alkyl.

Embodiment 59 provides the method of any one of Embodiments 55-58,wherein at each occurrence L^(CL) is independently chosen from—C(O)—NH—CH₂—NH—C(O)-M, —C(O)—NH—CH₂—CH₂—NH—C(O)-M,—C(O)—(O—CH₂—CH₂)_(n2)—O—C(O)-M, —C(O)—(O—CH₂—CH₂—CH₂)_(n2)—O—C(O)-M,—C(O)—O—C(CH₂—CH₃)(O—C(O)-M)₂, —CH₂—O—CH₂—C(—CH₂—O—R^(CL3))₃, —O-M,—CH₂—O—CH₂-M, —CH₂—O-M, —O—CH₂-M, N,N-boundtetrahydropyrimidin-2(1H)-one, N,3-bound pyrrolidone, 1,3-bound2-imidazolidone, and N,N-bound pyrrolidone-R^(CL1)-pyrrolidone whereinthe pyrrolidones are bound to R^(CL1) via the 3-positions, whereinR^(CL3) at each occurrence is —CH₂-M or H.

Embodiment 60 provides the method of any one of Embodiments 55-59,wherein c is about 1 to about 1,000,000

Embodiment 61 provides the method of any one of Embodiments 55-60,wherein c is about 5 to about 100,000.

Embodiment 62 provides the method of any one of Embodiments 1-61,further comprising combining the composition with an aqueous oroil-based fluid comprising a drilling fluid, stimulation fluid,fracturing fluid, spotting fluid, clean-up fluid, completion fluid,remedial treatment fluid, abandonment fluid, pill, acidizing fluid,cementing fluid, packer fluid, logging fluid, or a combination thereof,to form a mixture, wherein the placing the composition in thesubterranean formation comprises placing the mixture in the subterraneanformation.

Embodiment 63 provides the method of Embodiment 62, wherein thecementing fluid comprises Portland cement, pozzolana cement, gypsumcement, high alumina content cement, slag cement, silica cement, or acombination thereof.

Embodiment 64 provides the method of any one of Embodiments 1-63,wherein at least one of prior to, during, and after the placing of thecomposition in the subterranean formation, the composition is used inthe subterranean formation, at least one of alone and in combinationwith other materials, as a drilling fluid, stimulation fluid, fracturingfluid, spotting fluid, clean-up fluid, completion fluid, remedialtreatment fluid, abandonment fluid, pill, acidizing fluid, cementingfluid, packer fluid, logging fluid, or a combination thereof.

Embodiment 65 provides the method of any one of Embodiments 1-64,wherein the composition further comprises water, saline, aqueous base,oil, organic solvent, synthetic fluid oil phase, aqueous solution,alcohol or polyol, cellulose, starch, alkalinity control agent, aciditycontrol agent, density control agent, density modifier, emulsifier,dispersant, polymeric stabilizer, crosslinking agent, polyacrylamide,polymer or combination of polymers, antioxidant, heat stabilizer, foamcontrol agent, solvent, diluent, plasticizer, filler or inorganicparticle, pigment, dye, precipitating agent, rheology modifier,oil-wetting agent, set retarding additive, surfactant, corrosioninhibitor, gas, weight reducing additive, heavy-weight additive, lostcirculation material, filtration control additive, salt, fiber,thixotropic additive, breaker, crosslinker, gas, accelerator, curingretarder, pH modifier, chelating agent, scale inhibitor, enzyme, resin,water control material, polymer, oxidizer, a marker, Portland cement,pozzolana cement, gypsum cement, high alumina content cement, slagcement, silica cement, fly ash, metakaolin, shale, zeolite, acrystalline silica compound, amorphous silica, fibers, a hydratableclay, microspheres, pozzolan lime, or a combination thereof.

Embodiment 66 provides the method of any one of Embodiments 1-65,wherein the placing of the composition in the subterranean formationcomprises fracturing at least part of the subterranean formation to format least one subterranean fracture.

Embodiment 67 provides the method of any one of Embodiments 1-66,wherein the composition further comprises a proppant, a resin-coatedproppant, or a combination thereof.

Embodiment 68 provides the method of any one of Embodiments 1-67,wherein the placing of the composition in the subterranean formationcomprises pumping the composition through a tubular disposed in awellbore and into the subterranean formation.

Embodiment 69 provides the method of any one of Embodiments 1-68,wherein the placing of the composition in the subterranean formationcomprises pumping the composition through a drill string disposed in awellbore, through a drill bit at a downhole end of the drill string, andback above-surface through an annulus.

Embodiment 70 provides the method of Embodiment 69, further comprisingprocessing the composition exiting the annulus with at least one fluidprocessing unit to generate a cleaned composition and recirculating thecleaned composition through the wellbore.

Embodiment 71 provides a system for performing the method of any one ofEmbodiments 1-70, the system comprising:

a tubular disposed in the subterranean formation; and

a pump configured to pump the composition in the subterranean formationthrough the tubular.

Embodiment 72 provides a system for performing the method of any one ofEmbodiments 1-70, the system comprising:

a drill string disposed in a wellbore, the drill string comprising adrill bit at a downhole end of the drill string;

an annulus between the drill string and the wellbore; and

a pump configured to circulate the composition through the drill string,through the drill bit, and back above-surface through the annulus.

Embodiment 73 provides a method of treating a subterranean formation,the method comprising:

placing in a subterranean formation a composition comprising acrosslinked viscosifier polymer comprising repeating units having thestructure:

wherein

-   -   the repeating units are in a block, alternate, or random        configuration, and each repeating unit is independently in the        orientation shown or in the opposite orientation,    -   at each occurrence R^(A), R^(B), and R^(C) are independently        selected from the group consisting of —H and a substituted or        unsubstituted (C₁-C₅)hydrocarbyl,    -   at each occurrence L¹ and L² are each independently selected        from the group consisting of a bond and a substituted or        unsubstituted (C₁-C₄₀)hydrocarbyl interrupted or terminated with        0, 1, 2, or 3 of at least one of —S—, —O—, and substituted or        unsubstituted —NH—,    -   at each occurrence Z is independently chosen from a —OR^(D)        group, a —O—C(O)—R^(D) group, a —C(O)—NH₂ group, a —C(O)—NHR^(D)        group, a —C(O)—NR^(D) ₂ group, a —C(O)—OH group or a salt        thereof, a —C(O)—OR^(D) group, a —NR^(D)—C(O)—R^(D) group, and a        —(C₁₋₂₀)heterocyclyl, wherein the —(C₁₋₂₀)heterocyclyl is a        nitrogen-containing heterocycle substituent bound to the        ethylene repeating unit via a nitrogen atom in the heterocyclic        ring, and wherein R^(D) at each occurrence is independently        selected from —H and substituted or unsubstituted        (C₁-C₅₀)hydrocarbyl interrupted by 0, 1, 2, or 3 groups        independently selected from —O—, —S—, and substituted or        unsubstituted —NH—, and    -   at each occurrence L^(CL) is independently chosen from a        —((C₁-C₁₀)heterocyclylene)- and a -(substituted or unsubstituted        (C₁-C₄₀)hydrocarbylene)-M, wherein the (C₁-C₄₀)hydrocarbylene is        substituted or unsubstituted and is interrupted by 0, 1, 2, or 3        groups independently selected from —O—, —S—, substituted or        unsubstituted —NH—, and —((C₂-C₅)alkoxy)_(n)-, wherein at each        occurrence M is independently an ethylene repeating unit of the        same crosslinked viscosifier polymer molecule or an ethylene        repeating unit of another molecule of the crosslinked        viscosifier polymer,    -   wherein the crosslinked viscosifier polymer has about A^(mol)        mol % of the repeating unit comprising the —S(O)₂OR¹, wherein        A^(mol) is about 30 mol % to about 99 mol %, the crosslinked        viscosifier polymer has about B^(mol) mol % of the comonomer b,        wherein B^(mol) is about 0 mol % to about 70 mol %, wherein the        crosslinked viscosifier polymer has about C_(mol) mol % of the        comonomer c, wherein C^(mol) is about 0.01 mol % to about 30 mol        %.

Embodiment 74 provides a method of treating a subterranean formation,the method comprising:

placing in a subterranean formation a composition comprising acrosslinked viscosifier polymer comprising repeating units having thestructure:

wherein

-   -   the repeating units are in a block, alternate, or random        configuration, and each repeating unit is independently in the        orientation shown or in the opposite orientation,    -   at each occurrence R^(A), R^(B), and R^(C) are independently        selected from the group consisting of —H and (C₁-C₅)alkyl,    -   at each occurrence Z is independently chosen from an —OH group,        a —OR^(D) group, a —O—C(O)—R^(D) group, a —C(O)—NH₂ group, a        —C(O)—OH group or a salt or (C₁-C₅) alkyl ester thereof, a        —C(O)—OR^(D) group, and —N-pyrrolidinyl, wherein R^(D) at each        occurrence is independently (C₁-C₅)alkyl,    -   at each occurrence L^(CL) is independently chosen from        —C(O)—NH—CH₂—NH—C(O)-M, —C(O)—NH—CH₂—CH₂—NH—C(O)-M,        —C(O)—(O—CH₂—CH₂)_(n2)—O—C(O)-M,        —C(O)—(O—CH₂—CH₂—CH₂)_(n2)—O—C(O)-M,        —C(O)—O—C(CH₂—CH₃)(O—C(O)-M)₂, —CH₂—O—CH₂—C(—CH₂—O—R^(CL3))₃,        —O-M, —CH₂—O—CH₂-M, —CH₂—O-M, —O—CH₂-M, N,N-bound        tetrahydropyrimidin-2(1H)-one, N,3-bound pyrrolidone, 1,3-bound        2-imidazolidone, and N,N-bound pyrrolidone-R^(CL1)-pyrrolidone        wherein the pyrrolidones are bound to R^(CL1) via the        3-positions, wherein R^(CL3) at each occurrence is —CH₂-M or H,        wherein at each occurrence M is independently an ethylene        repeating unit of the same crosslinked viscosifier polymer        molecule or an ethylene repeating unit of another molecule of        the crosslinked viscosifier polymer, and    -   wherein the crosslinked viscosifier polymer has about A^(mol)        mol % of the repeating unit comprising the —S(O)₂OR¹, wherein        A^(mol) is about 30 mol % to about 99 mol %, the crosslinked        viscosifier polymer has about B^(mol) mol % of the comonomer b,        wherein B^(mol) is about 0 mol % to about 70 mol %, wherein the        crosslinked viscosifier polymer has about C^(mol) mol % of the        comonomer c, wherein C^(mol) is about 0.01 mol % to about 30 mol        %, wherein A^(mol)+B^(mol)+C^(mol) is about 100 mol %.

Embodiment 75 provides a system comprising:

a composition comprising a crosslinked viscosifier polymer comprising anethylene repeating unit comprising an —S(O)₂OR¹ group wherein at eachoccurrence R¹ is independently chosen from —H, substituted orunsubstituted (C₁-C₂₀)hydrocarbyl, and a counterion; and

a subterranean formation comprising the composition therein.

Embodiment 76 provides the system of Embodiment 75, further comprising

a drill string disposed in a wellbore, the drill string comprising adrill bit at a downhole end of the drill string;

an annulus between the drill string and the wellbore; and

a pump configured to circulate the composition through the drill string,through the drill bit, and back above-surface through the annulus.

Embodiment 77 provides the system of Embodiment 76, further comprising afluid processing unit configured to process the composition exiting theannulus to generate a cleaned drilling fluid for recirculation throughthe wellbore.

Embodiment 78 provides the system of any one of Embodiments 75-77,further comprising

a tubular disposed in the subterranean formation; and

a pump configured to pump the composition in the subterranean formationthrough the tubular.

Embodiment 79 provides a composition for treatment of a subterraneanformation, the composition comprising:

a crosslinked viscosifier polymer comprising an ethylene repeating unitcomprising an —S(O)₂OR¹ group wherein at each occurrence R¹ isindependently chosen from —H, substituted or unsubstituted(C₁-C₂₀)hydrocarbyl, and a counterion.

Embodiment 80 provides the composition of Embodiment 79, wherein thecomposition is a composition for drilling into a reservoir in asubterranean formation.

Embodiment 81 provides a composition for treatment of a subterraneanformation, the composition comprising:

a crosslinked viscosifier polymer comprising repeating units having thestructure:

wherein

-   -   the repeating units are in a block, alternate, or random        configuration, and each repeating unit is independently in the        orientation shown or in the opposite orientation,    -   at each occurrence R^(A), R^(B), and R^(C) are independently        selected from the group consisting of —H and a substituted or        unsubstituted (C₁-C₅)hydrocarbyl,    -   at each occurrence L¹ and L² are each independently selected        from the group consisting of a bond and a substituted or        unsubstituted (C₁-C₄₀)hydrocarbyl interrupted or terminated with        0, 1, 2, or 3 of at least one of —S—, —O—, and substituted or        unsubstituted —NH—,    -   at each occurrence Z is independently chosen from a —OR^(D)        group, a —O—C(O)—R^(D) group, a —C(O)—NH₂ group, a —C(O)—NHR^(D)        group, a —C(O)—NR^(D) ₂ group, a —C(O)—OH group or a salt        thereof, a —C(O)—OR^(D) group, a —NR^(D)—C(O)—R^(D) group, and a        —(C₁₋₂₀)heterocyclyl, wherein the —(C₁₋₂₀)heterocyclyl is a        nitrogen-containing heterocycle substituent bound to the        ethylene repeating unit via a nitrogen atom in the heterocyclic        ring, and wherein R^(D) at each occurrence is independently        selected from —H and substituted or unsubstituted        (C₁-C₅₀)hydrocarbyl interrupted by 0, 1, 2, or 3 groups        independently selected from —O—, —S—, and substituted or        unsubstituted —NH—,    -   at each occurrence L^(CL) is independently chosen from a        —((C₁-C₁₀)heterocyclylene)- and a -(substituted or unsubstituted        (C₁-C₄₀)hydrocarbylene)-M, wherein the (C₁-C₄₀)hydrocarbylene is        substituted or unsubstituted and is interrupted by 0, 1, 2, or 3        groups independently selected from —O—, —S—, substituted or        unsubstituted —NH—, and —((C₂-C₅)alkoxy)_(n)-, wherein at each        occurrence M is independently an ethylene repeating unit of the        same crosslinked viscosifier polymer molecule or an ethylene        repeating unit of another molecule of the crosslinked        viscosifier polymer, and

wherein the crosslinked viscosifier polymer has about A^(mol) mol % ofthe repeating unit comprising the —S(O)₂OR¹, wherein A^(mol) is about 30mol % to about 99 mol %, the crosslinked viscosifier polymer has aboutB^(mol) mol % of the comonomer b, wherein B^(mol) is about 0 mol % toabout 70 mol %, wherein the crosslinked viscosifier polymer has aboutC^(mol) mol % of the comonomer c, wherein C^(mol) is about 0.01 mol % toabout 30 mol %.

Embodiment 82 provides a composition for treatment of a subterraneanformation, the composition comprising:

a crosslinked viscosifier polymer comprising repeating units having thestructure:

wherein

-   -   the repeating units are in a block, alternate, or random        configuration, and each repeating unit is independently in the        orientation shown or in the opposite orientation,    -   at each occurrence R^(A), R^(B), and R^(C) are independently        selected from the group consisting of —H and (C₁-C₅)alkyl,    -   at each occurrence Z is independently chosen from an —OH group,        a —OR^(D) group, a —O—C(O)—R^(D) group, a —C(O)—NH₂ group, a        —C(O)—OH group or a salt or (C₁-C₅) alkyl ester thereof, a        —C(O)—OR^(D) group, and —N-pyrrolidinyl, wherein R^(D) at each        occurrence is independently (C₁-C₅)alkyl,    -   at each occurrence L^(CL) is independently chosen from        —C(O)—NH—CH₂—NH—C(O)-M, —C(O)—NH—CH₂—CH₂—NH—C(O)-M,        —C(O)—(O—CH₂—CH₂)_(n2)—O—C(O)-M,        —C(O)—(O—CH₂—CH₂—CH₂)_(n2)—O—C(O)-M,        —C(O)—O—C(CH₂—CH₃)(O—C(O)-M)₂, —CH₂—O—CH₂—C(—CH₂—O—R^(CL3))₃,        —O-M, —CH₂—O—CH₂-M, —CH₂—O-M, —O—CH₂-M, N,N-bound        tetrahydropyrimidin-2(1H)-one, N,3-bound pyrrolidone, 1,3-bound        2-imidazolidone, and N,N-bound pyrrolidone-R^(CL1)-pyrrolidone        wherein the pyrrolidones are bound to R^(CL1) via the        3-positions, wherein R^(CL3) at each occurrence is —CH₂-M or H,        wherein at each occurrence M is independently an ethylene        repeating unit of the same crosslinked viscosifier polymer        molecule or an ethylene repeating unit of another molecule of        the crosslinked viscosifier polymer, and

wherein the crosslinked viscosifier polymer has about A^(mol) mol % ofthe repeating unit comprising the —S(O)₂OR¹, wherein A^(mol) is about 30mol % to about 99 mol %, the crosslinked viscosifier polymer has aboutB^(mol) mol % of the comonomer b, wherein B^(mol) is about 0 mol % toabout 70 mol %, wherein the crosslinked viscosifier polymer has aboutC^(mol) mol % of the comonomer c, wherein C^(mol) is about 0.01 mol % toabout 30 mol %, wherein A^(mol)+B^(mol)+C^(mol) is about 100 mol %.

Embodiment 83 provides a method of preparing a composition for treatmentof a subterranean formation, the method comprising:

forming a composition comprising a crosslinked viscosifier polymercomprising an ethylene repeating unit comprising an —S(O)₂OR¹ groupwherein at each occurrence R¹ is independently chosen from —H,substituted or unsubstituted (C₁-C₂₀)hydrocarbyl, and a counterion.

Embodiment 84 provides the composition, method, or system of any one orany combination of Embodiments 1-83 optionally configured such that allelements or options recited are available to use or select from.

What is claimed is:
 1. A method of treating a subterranean formation,the method comprising: placing in a subterranean formation a compositioncomprising a crosslinked viscosifier polymer comprising an ethylenerepeating unit comprising an —S(O)₂OR¹ group wherein at each occurrenceR¹ is independently chosen from —H, substituted or unsubstituted(C₁-C₂₀)hydrocarbyl, and a counterion, wherein the crosslinkedviscosifier polymer is a homopolymer having about C^(mol) mol % of acrosslinker, wherein C^(mol) is about 2 mol % to about 30 mol %, whereinthe composition comprises at least one of an aqueous liquid and/or awater-miscible liquid in an amount of about 30 wt. % to about 99.99 wt.% by weight of the composition; wherein the crosslinked viscosifier iscrosslinked via at least one crosslinker selected frommethylenebisacrylamide, ethylenebisacrylamide, ethylene glycoldimethacrylate, a polyethylene glycol dimethacrylate,1,1,1-trimethylolpropane trimethacrylate, divinyl ether, diallyl ether,a vinyl or allyl ether of a polyglycol or a polyol,N,N′-divinylethyleneurea, a divinylbenzene,divinyltetrahydropyrimidin-2(1H)-one, a diene, an allyl amine,N-vinyl-3(E)-ethylidene pyrrolidone, and ethylidenebis(N-vinylpyrrolidone).
 2. The method of claim 1, wherein thecomposition is a drill-in fluid, wherein the method comprises drillinginto a petroleum reservoir in the subterranean formation using thecomposition.
 3. The method of claim 1, wherein the composition has lessthan 5 wt % clay.
 4. The method of claim 1, wherein the aqueous liquidcomprises at least one of water, brine, produced water, flowback water,brackish water, and sea water.
 5. The method of claim 1, wherein at 49°C. at standard pressure at 3 rpm to 6 rpm the composition has a shearstress of about 1 lb/100 ft² to about 40 lb/100 ft².
 6. The method ofclaim 1, wherein at 49° C. at standard pressure at 200 rpm to 600 rpmthe composition has a shear stress of about 15 lb/100 ft² to about 150lb/100 ft².
 7. The method of claim 1, wherein at 49° C. at standardpressure the composition has a yield point of about 10 lb/100 ft² toabout 80 lb/100 ft².
 8. The method of claim 1, wherein the crosslinkedviscosifier polymer has about A^(mol) mol % of the repeating unitcomprising the —S(O)₂OR¹, wherein A^(mol) is about 30 mol % to about 99mol %.
 9. The method of claim 1, wherein the crosslinked viscosifierpolymer comprises repeating units having the structure:

wherein the repeating units are in a block, alternate, or randomconfiguration, and each repeating unit is independently in theorientation shown or in the opposite orientation, at each occurrenceR^(A), R^(B), and R^(C) are independently selected from the groupconsisting of —H and a substituted or unsubstituted (C₁-C₅)hydrocarbyl,and at each occurrence L¹ is independently selected from the groupconsisting of a bond and a substituted or unsubstituted(C₁-C₄₀)hydrocarbyl interrupted or terminated with 0, 1, 2, or 3 of atleast one of —S—, —O—, and substituted or unsubstituted —NH—.
 10. Themethod of claim 1, wherein at each occurrence R¹ is independentlyselected from the group consisting of —H, Na⁺, K⁺, Li⁺, NH₄ ⁺, Zn⁺,Ca²⁺, Zn²⁺, Al³⁺, Mg²⁺, and NR^(E) ₄, wherein at each occurrence R^(E)is independently chosen from —H and substituted or unsubstituted(C₁-C₃₀)hydrocarbyl interrupted by 0,1,2, or 3 groups independentlychosen from —O—, —S—, and substituted or unsubstituted —NH—, wherein twoor three R^(E) groups together form a substituted or unsubstituted(C₁-C₃₀) hydrocarbylene or (C₁-C₃₀) hydrocarbyl interrupted by 0,1,2, or3 groups independently chosen from —O—, —S—, and substituted orunsubstituted —NH—.
 11. The method of claim 1, wherein the ethylenerepeating unit comprising the —S(O)₂OR¹ group is a2-acrylamido-2-methylpropanesulfonic acid repeating unit or a salt or(C₁-C₅)alkyl ester thereof.
 12. The method of claim 1, furthercomprising combining the composition with an aqueous or oil-based fluidcomprising a drilling fluid, stimulation fluid, fracturing fluid,spotting fluid, clean-up fluid, completion fluid, remedial treatmentfluid, abandonment fluid, pill, acidizing fluid, cementing fluid, packerfluid, logging fluid, or a combination thereof, to form a mixture,wherein the placing the composition in the subterranean formationcomprises placing the mixture in the subterranean formation.